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FAQ Get answers to ELD-related questions

FMCSA provides answers to frequently asked questions about ELDs. Consult these FAQs when you have an ELD-related question, as the answer may already be at your fingertips.

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Yes. An ELD can be on a smartphone or other wireless device if the device meets the ELD rule's technical specifications.

Last Updated : March 15, 2017

Yes. A driver may use a portable ELD. A portable ELD must be mounted in a fixed position during commercial motor vehicle (CMV) operation (CMV) and visible to the driver from a normal seated driving position. This information can be found in the ELD Rule section 395.22(g).

Last Updated : March 22, 2017

While not required, if the motor carrier configured the driver user account to authorize a special driving category, then the graph-grid will overlay periods using a different style line (such as dashed, dotted line, or shading) in accordance with section 4.8.1.3(c)(1) of the ELD Functional Specifications. The appropriate abbreviation must also be indicated on the graph-grid.

If the motor carrier does not configure the driver user account to authorize special driving categories, then the driver must annotate the beginning and end of the applicable special driving category.

Last Updated : July 12, 2017

Yes. However, the ELD must comply with the ELD rule's technical specifications. The ELD may use alternative sources to obtain or estimate the required vehicle parameters, in accordance with the accuracy requirements in Section 4.3.1 of the ELD rule.

Last Updated : March 22, 2017

An edit is a change to an electronic logging device (ELD) record that does not overwrite the original record, while an annotation is a note related to a record, update, or edit that a driver or authorized support personnel may input to the ELD. Section 49 CFR 395.30(c)(2) requires that all edits, whether made by a driver or the motor carrier, be annotated to document the reason for the change. For example, an edit showing time being switched from "off duty" to "on-duty not driving" could be annotated by the carrier to note, "Driver logged training time incorrectly as off duty." This edit and annotation would then be sent to the driver for approval.

Last Updated : March 28, 2017

Yes. A driver can use annotations to indicate the beginning and end of a period of authorized personal commercial vehicle use, or yard moves, as well as other special driving categories, such as adverse driving conditions (49 CFR 395.1(b)) or oilfield operations (49 CFR 395.1(d)).

Last Updated : March 28, 2017

Both the driver and authorized carrier staff can make limited edits to an ELD record to correct mistakes or add missing information. All edits must include a note (annotation) to explain the reason for the edit. In addition, the driver must confirm (certify) that any carrier edit is accurate, and resubmit the records. If the driver chooses not to re-certify RODs, this is also reflected in the ELD record. The ELD must keep the original, unedited record, along with the edits. Example: a carrier edits a record to switch a period of time from "off-duty" to "on-duty not driving", with a note that explains "Driver logged training time incorrectly as off-duty". The edit and annotation are sent to the driver to verify. The edit is not accepted until the driver confirms it and resubmits the RODS.

Last Updated : March 28, 2017

Yes. The original ELD records are retained even when allowed edits and annotations are made. If the driver cannot independently access the records from the ELD, the motor carrier must provide access on request. However, the right to access is limited to a six-month period, consistent with the period during which a motor carrier must retain drivers' records of duty status (RODS).

Last Updated : March 28, 2017

No. An ELD automatically records all of the time that a CMV is in motion as driving time that cannot be edited or changed to non-driving time.

Last Updated : March 28, 2017

For a reset or replaced ELD, the ELD rule requires data or documents showing the driver's records of duty status (RODS) history in the vehicle. This data would include the driver's past 7 days of RODS, either loaded into the "new" ELD or in paper format to be provided at roadside.

Last Updated : March 28, 2017

For team drivers, the driver account associated with the driving time records may be edited and reassigned between the team drivers, if there was a mistake resulting in a mismatch between the actual driver and the driver recorded by the ELD, and if both team drivers were indicated in one another's records as a co-driver. Each co-driver must confirm the change for the corrective action to take effect.

Last Updated : April 03, 2017

A driver must review any unassigned driving time when he or she logs into the ELD. If the unassigned records do not belong to the driver, the driver must indicate that in the ELD record. If driving time logged under this unassigned account belongs to the driver, the driver must add that driving time to his or her own record.

Last Updated : April 03, 2017

A motor carrier must either explain why the time is unassigned or assign the time to the appropriate driver. The motor carrier must retain unidentified driving records for at least six months as a part of its hours-of-service (HOS) ELD records and make them available to authorized safety officials.

Last Updated : April 03, 2017

Yes, a driver can be assigned unidentified driver records recorded under the Unidentified Driver profile and indicate a special driving category. However, an ELD must not allow automatically recorded driving time for a driver to be shortened or altered in any way.

Last Updated : December 19, 2018

Yes, a driver can edit their record after erroneously accepting a driving event that was originally recorded under the Unidentified Driver profile. The ELD must prompt the driver to annotate edits. In addition, the carrier can suggest the edit which can be routed to the driver for confirmation.

Last Updated : December 19, 2018

An ELD automatically records the following data elements at certain intervals: date; time; location information; engine hours; vehicle miles; and identification information for the driver, authenticated user, vehicle, and motor carrier.

Last Updated : April 06, 2017

Location data must be recorded by an ELD at 60-minute intervals when the vehicle is in motion, and when the driver powers up and shuts down the engine, changes duty status, and indicates personal use or yard moves.

Last Updated : April 06, 2017

No. Vehicle location information is not sufficiently precise to identify street addresses. For each change in duty status, the ELD must convert automatically captured vehicle position in latitude/longitude coordinates into geo-location information that indicates the approximate distance and direction to an identifiable location corresponding to the name of a nearby city, town, or village, with a State abbreviation.

Last Updated : July 12, 2017

No. ELDs are not required to collect data on vehicle speed, braking action, steering function or other vehicle performance parameters. ELDs are only required to collect data to determine compliance with hours-of-service (HOS) regulations.

Last Updated : April 06, 2017

No. The specifications for ELDs do not include requirements to control the vehicle. An ELD is a recording device that records vehicle parameters through its synchronization to the vehicle’s engine, and allows for entries related to a driver’s record of duty status (RODS).

Last Updated : April 06, 2017

During on-duty driving periods, the location accuracy is approximately within a 1-mile radius. When a driver operates a CMV for personal use, the position reporting accuracy would be approximately within a 10-mile radius.

Last Updated : April 06, 2017

An ELD must be integrally synchronized with the engine of the commercial motor vehicle (CMV). Engine synchronization means monitoring engine operation to automatically capture the engine power status, vehicle motion status, miles driven, and engine hours.

Last Updated : April 06, 2017

No, the ELD must be able to monitor engine operation to automatically capture required data. A GPS is not integrally synchronized with a vehicle's engine, and cannot be a substitute for required ECM data to comply with the ELD rule.

Last Updated : April 10, 2017

Yes. FMCSA allows, but does not require, warning or notification to drivers when they are nearing their HOS limits.

Last Updated : April 10, 2017

An ELD must automatically switch to driving mode once the commercial motor vehicle (CMV) is moving up to a set speed threshold of five miles per hour. As a result, the in-motion state must not be configured greater than five miles per hour. The vehicle will be considered stopped once its speed falls to zero miles per hour and stays at zero miles per hour for three consecutive seconds.

Last Updated : April 10, 2017

When the duty status is set to driving, and the commercial motor vehicle (CMV) has not been in motion for five consecutive minutes, the ELD must prompt the driver to confirm a continued driving status or enter the proper duty status. If the driver does not respond to the ELD prompt within one minute, the ELD must automatically switch the duty status to on-duty not driving.

Last Updated : April 10, 2017

When the personal conveyance status is selected (as allowed and configured by the motor carrier), the CMV's location is recorded with a lower level of precision (i.e., an approximate 10-mile radius). Personal conveyance will be reflected on the ELD using a different style line (such as dashed or dotted line).

Last Updated : July 12, 2017

In the event of team drivers, the ELD must display the data for both co-drivers who are logged into the system.

Last Updated : April 12, 2017

Yes. The driver who is not operating the vehicle may make entries over his or her own records when the vehicle is in motion. However, co-drivers cannot switch driving roles on the ELD when the vehicle is in motion.

Last Updated : April 17, 2017

No. The ELD will capture all entered duty statuses, and there is no minimum amount of time that these statuses must or should be engaged. While longstanding industry and enforcement practices may have relied upon minimum intervals of 15 minutes in handwritten records of duty status (RODS), an ELD provides a more accurate accounting of drivers' time. This should not be construed to indicate that the activities electronically recorded as less than 15 minutes are suspect, only that the time actually required to complete the task may be less that what had been traditionally noted in the paper RODS.

Last Updated : April 17, 2017

The device manufacturer may offer that service as part of a fleet management package but mileage tracking for tax reporting purposes is not part of the ELD data established in Part 395.

Last Updated : December 12, 2017

According to the ELD rule technical specifications, an ELD must support one of two options for electronic data transfer:

  1. The first option is a "telematics" transfer type ELD. At a minimum, it must electronically transfer data to an authorized safety official on demand via wireless Web services and email.
  2. The second option is a "local" transfer type ELD. At a minimum, it must electronically transfer data to an authorized safety official on demand via USB2.0 and Bluetooth®.
To ensure that law enforcement is always able to receive the hours-of-service (HOS) data during a roadside inspection, a driver must be able to provide either the display or a printout when an authorized safety official requests a physical display of the information.

Last Updated : November 22, 2019

Authorized safety officials who conduct roadside enforcement activities (i.e., traffic enforcement and inspections) or compliance safety investigations will have the option of choosing a minimum of one electronic data transfer method (wireless Web services or email) and one "local" electronic data transfer method (USB2.0 or Bluetooth) for the electronic transfer of ELD data, depending on the type of ELD.

Last Updated : April 17, 2017

If a driver is using a "local" ELD with USB 2.0 capabilities, an authorized safety official will provide a secure USB device to allow the driver to electronically transfer data from the ELD to the official. The driver will return the USB device to the safety official, who will transfer the data to a computing device.

Last Updated : April 18, 2017

If the driver is using a "telematics" ELD with email capabilities, the authorized safety official will request that the electronic data transfer file be sent as an attachment to an e-mail. This e-mail address is preprogramed in the ELD by the vendor. The safety official will provide the driver with a routing code to reference in the email.

Last Updated : July 12, 2017

While the local Bluetooth requires the use of web services, local Bluetooth data transfer only requires the safety official to have internet connectivity and not the ELD. The driver's/motor carrier's ELD will use the safety official's internet connection to transfer data. The internet connection between the ELD and the safety official will be limited and can only be used for the purpose of transferring the ELD data via the web service. During Bluetooth data transfer, the driver/motor carrier must make the ELD discoverable. Once the ELD detects the safety official's laptop, the safety official will provide the driver/motor carrier with a Bluetooth code to enter into the ELD and confirm Bluetooth connectivity between the safety official's laptop and the ELD. Once the connection between the safety official's laptop and the ELD has been confirmed, the safety official will provide the driver/motor carrier with the safety official's unique code, and the driver/motor carrier will transfer the ELD data to web services for the safety official to retrieve.

Last Updated : December 14, 2017

No. If the electronic means for transferring data is unavailable or fails, the driver can still be compliant by showing either a printout or the actual ELD display of their RODS.

Last Updated : April 18, 2017

If there are cellular network limitations that prevent the ELD from transferring data to the Federal Motor Carrier Safety Administration's web services, the safety official will use the ELD's display screen or printout to verify compliance with the U.S. HOS regulations.

Last Updated : February 13, 2018

Yes. An ELD must monitor its compliance with the ELD technical requirements and detect malfunctions and data inconsistencies related to power, data synchronization, missing data, timing, positioning, data recording, data transfer, and unidentified driver records requirements. The ELD output will identify these data diagnostic and malfunction events and their status as either "detected" or "cleared." Typically, a driver can follow the ELD provider's and the motor carrier's recommendations to resolve the data inconsistencies that generate an ELD data diagnostic event, while a motor carrier must correct a malfunction.

Last Updated : April 18, 2017

"Power data diagnostic events" occur when an ELD is not powered and fully functional within one minute of the vehicle's engine receiving power and does not remain powered for as long as the vehicle's engine stays powered.

"Power compliance malfunctions" occur when an ELD is not powered for an aggregated in-motion driving time of 30 minutes or more over a 24-hour period across all driver profiles.

Last Updated : April 18, 2017

"Engine synchronization data diagnostic events" occur when an ELD loses ECM connectivity to any of the required data sources (engine power status, vehicle motion status, miles driven, and engine hours) and can no longer acquire updated values for the required ELD parameters within five seconds of the need.

"Engine synchronization compliance malfunctions" occur when ECM connectivity to any of the required data sources (engine power status, vehicle motion status, miles driven, and engine hours) is lost for more than 30 minutes during a 24-hour period aggregated across all driver profiles.

Last Updated : April 18, 2017

A "timing compliance malfunction" occurs when the ELD can no longer meet the underlying compliance requirement to record Coordinated Universal Time (UTC), where ELD time must be synchronized with UTC, not to exceed an absolute deviation of 10 minutes at any time.

Last Updated : April 18, 2017

When an ELD fails to acquire a valid position measurement within 5 miles of the commercial motor vehicle moving and 60 minutes has passed, a "position compliance malfunction" will be recorded in the data diagnostic.

Last Updated : April 18, 2017

A "data recording compliance malfunction" occurs when an ELD can no longer record or retain required events or retrieve recorded logs that are not kept remotely by the motor carrier.

Last Updated : April 18, 2017

A "missing required data elements data diagnostic event" occurs when any required data field is missing at the time of its recording.

Last Updated : April 18, 2017

A "data transfer data diagnostic event" occurs when the operation of the data transfer mechanism(s) is not confirmed.
A "data transfer compliance" malfunction occurs when the ELD stays in the unconfirmed data transfer mode following the next three consecutive monitoring checks.

Last Updated : April 18, 2017

An "unidentified driving records data diagnostic event" occurs when more than 30 minutes of driving time for an unidentified driver is recorded within a 24-hour period.

Last Updated : April 18, 2017

An ELD must display a single visual malfunction indicator on the ELD’s display or on a stand-alone indicator for all drivers using the ELD. The visual signal must be visible to the driver, be continuously communicated to the driver when the ELD is powered, and clearly illuminate an active malfunction. An ELD must also display a single visual data diagnostics indicator, apart from the malfunction indicator, for active data diagnostics events. The ELD may also provide an audible signal for the data diagnostics indicator. A malfunction is a situation in which an ELD is not working properly. A malfunction affects the integrity of the device and its compliance, and requires the motor carrier to repair, replace, or service the ELD.

An ELD must display a malfunction signal (or indicator) such as a light, symbol, or text on the ELD or on a stand-alone display. The malfunction signal must be visible to the driver and display function status whenever the ELD is powered on. It must also light up to draw attention to an active malfunction.

An ELD must also include a diagnostics indicator to display active diagnostic events. Data diagnostic events note data inconsistencies that a driver can typically resolve by following the motor carrier’s or ELD provider’s recommendations.

Last Updated : November 22, 2019

If an ELD malfunctions, the safety official can decide what methods of record retrieval not specified in the ELD rule are acceptable. This includes options like accepting HOS records by fax.

Last Updated : February 13, 2018

No. The ELD rule requires that the ability to transfer data electronically, and produce the driver's HOS as either an ELD printout or display.

Last Updated : February 13, 2018

Yes. ELD user accounts can be created on individual ELDs or the ELD support system.

Last Updated : April 21, 2017

Each driver account must be created by entering the driver's license number and the State of jurisdiction that issued the driver's license. The driver's license information is only required to set up the driver's user account and verify his or her identity; it is not used as part of the daily process for entering duty status information.

Last Updated : April 21, 2017

A motor carrier must assign only one ELD driver account for each of its drivers required to use an ELD. An ELD must not allow the creation of more than one driver account associated with a driver's license for a given motor carrier. The motor carrier is also responsible for establishing requirements for unique user identifications and passwords.

Last Updated : April 21, 2017

No. Each driver should have one account that allows him or her to log in and perform driver-related functions. All other administrative functions should be based on the discretion of each company or its provider. This means a driver who is also the owner of the company would have a single account authorizing entries as a driver, and a separate account for administrative functions. Accounts can be created on the ELD or the ELD support system.

Last Updated : April 21, 2017

Section 395.22(b)(2)(i) states that a motor carrier must manage ELD accounts. Therefore, the driver's license information must be updated in the ELD. If the data files from an individual's old and new driver license files cannot be merged, the driver must either manually enter the previous duty status information or provide a printout from the older HOS to provide an accurate accounting of the duty status for the current and previous seven days for authorized safety officials.

Last Updated : April 21, 2017

No. The ELD rule prohibits multiple driver accounts for one driver. The motor carrier must proactively change the driver's status to and from exempt and non-exempt.

Last Updated : July 12, 2017

The ELD rule includes a procedure to remove a listed registered device from the FMCSA website, to provide additional assurance to motor carriers that ELDs on the vendor registration website are compliant. This procedure also protects an ELD vendor's interest in its product.

Last Updated : April 21, 2017

The table below compares the technical specifications in the AOBRD rule (49 CFR 395.15) and the ELD rule.

Feature/Function 1988 AOBRD Rule ELD Rule
Integral Synchronization Integral synchronization required, but term not defined in the Federal Motor Carrier Safety Regulations (FMCSRs). Integral synchronization interfacing with the CMV engine electronic control module (ECM), to automatically capture engine power status, vehicle motion status, miles driven, engine hours. (CMVs older than model year 2000 exempted.)
Recording Location Information of Commercial Motor Vehicle (CMV) Required at each change of duty status. Manual or automated. Requires automated entry at each change of duty status, at 60-minute intervals while CMV is in motion, at engine-on and engine- off instances, and at beginning and end of personal use and yard moves.
Graph Grid Display Not required – "time and sequence of duty status changes." An ELD must be able to present a graph grid of driver's daily duty status changes either on a display or on a printout.
Hours of Service (HOS) Driver Advisory Messages Not addressed. HOS limits notification is not required. "Unassigned driving time/miles" warning must be provided upon login.
Device "Default" Duty Status Not addressed. On-duty not driving status, when CMV has not been in-motion for five consecutive minutes, and driver has not responded to an ELD prompt within one minute. No other non-driver-initiated status change is allowed.
Clock Time Drift Not addressed. ELD time must be synchronized to Universal Coordinated Time (UTC); absolute deviation must not exceed 10 minutes at any time.
Communications MethodsNot addressed – focused on interface between AOBRD support systems and printers. Two Options:
"Telematics": As a minimum, the ELD must transfer data via both wireless Web services and wireless e-mail.
"Local Transfer": As a minimum, the ELD must transfer data via both USB 2.0 and Bluetooth.
Both types of ELDs must be capable of displaying a standardized ELD data set to authorized safety officials via display or printout.
Resistance to Tampering AOBRD and support systems must be tamperproof, to the maximum extent practical. An ELD must not permit alteration or erasure of the original information collected concerning the driver's ELD records or alteration of the source data streams used to provide that information. ELD must support data integrity check functions.
Identification of Sensor Failures and Edited DataAOBRD must identify sensor failures and edited data. An ELD must have the capability to monitor its compliance (engine connectivity, timing, positioning, etc.) for detectable malfunctions and data inconsistencies. An ELD must record these occurrences.

Last Updated : April 21, 2017

Yes, if a driver that operates in Canada or in Mexico operates and drives in the U.S., and does not meet one of the ELD exemptions, said driver must use an ELD while operating in the U.S.

Last Updated : November 22, 2019

Yes. The driver can add the VIN manually if the ELD cannot retrieve the VIN from the vehicle engine data.

Last Updated : February 13, 2018

Yes. A driver may use a portable handheld ELD, smartphone, or other wireless device if the device meets the ELD rule's technical specifications and is on the Registered ELD list on FMCSA's website. While operating in the U.S., the portable ELD unit, smartphone, or other wireless device must be mounted in a fixed position during the vehicle operation and must be visible to the driver from a normal seated position.

Last Updated : February 13, 2018

No. If the driver is subject to the ELD rule, the driver must use one of the following: a self-certified and registered ELD, registered ELD software installed on a portable device, or a qualifying AOBRD (so long as the AOBRD was installed and in use prior to December 17, 2017).

Last Updated : February 13, 2018

Yes. When operating in the United States, a motor carrier must use an electronic logging device that displays vehicle road miles information in units of whole miles.

Last Updated : February 13, 2018

The technical specifications in the ELD rule ensure that manufacturers develop compliant devices and systems for uniform enforcement of hours of service.

Last Updated : April 21, 2017

No, FMCSA will not provide the RODS application for vendors to test against. Compliance test procedures are available on the ELD website to allow vendors to test their devices’ compliance with the ELD rule technical specifications.

Last Updated : April 21, 2017

No. The ECM and ELD may be connected by serial or Control Area Network communication protocols. Hard wiring to the J1939 plug and Bluetooth connectivity are examples of methods of receiving the data from the ECM or vehicle data bus.

Last Updated : April 21, 2017

An ELD must use onboard sensors and data record history to identify instances when it may not have complied with the power requirements specified in the ELD rule.

Last Updated : April 21, 2017

The manufacture must register each model and version and self-certify that each particular ELD is compliant with the ELD rule. The manufacturer must decide whether a firmware update is sufficiently significant to change the registration information. FMCSA did not specify parameters for version revisions.

Last Updated : April 21, 2017

Vendors should register each device bundle if they have different operating systems (e.g., an iOS-based bundle and an Android-based bundle would be considered two registered devices).

Last Updated : April 21, 2017

No. ELD manufacturers may use any test procedure they choose and note this in the registration. FMCSA will not provide a third-party testing service. FMCSA will only investigate devices that are suspected of not conforming to specifications, and will conduct testing with the FMCSA compliance test procedure during its investigation.

Last Updated : April 21, 2017

FMCSA does not specify testing requirements for connectivity with the vehicle. Each ELD provider is responsible for connectivity testing.

Last Updated : April 21, 2017

FMCSA showed a CMV number, as an example, in the header output file. The intent was to allow an additional vehicle identification number if an operator had numbered vehicles and chose to add company-assigned numbers to the CMV header data.

Last Updated : April 21, 2017

Yes. Section 4.8.1.3, requires the inspected driver’s profile and the unidentified driver profile to be available as separate reports at roadside either by printout or display. If there are no unidentified driver records existing on the ELD for the current 24-hour period or for any of the previous 7 consecutive days, an ELD does not need to print or display unidentified driver records for the authorized safety official. Otherwise, both reports must be printed or displayed and provided to the authorized safety official.

Last Updated : July 12, 2017

The ELD is required to obtain and display the ECM value at all times. Safety officials will use the odometer value reported on the ELD. Note that documentation of engine changes is required by 49 CFR Part 379 Appendix A to be maintained at the carrier’s place of business.

Last Updated : December 12, 2017

You should review the technical specifications included in the final rule, along with the FMCSA’s compliance test procedures. You are required to self-certify your device, stating that it is in compliance with all of the technical specifications. The compliance test procedures are designed to assist manufacturers in determining whether their product meets the ELD rule requirements. While ELD manufacturers are not required to use FMCSA’s compliance test procedure, they are required to ensure that their products are compliant with the ELD rule.

Last Updated : April 21, 2017

The ELD must set the “Event Record Origin” of the ELD record to “2” (edited or entered by the driver).

Last Updated : November 07, 2019

The ELD must set the “Event Record Origin” of the ELD record to “2” (edited or entered by the driver).

Last Updated : November 07, 2019

Yes, but only if the driving time was recorded by the ELD while the vehicle was powered off and the vehicle was not in motion during the period that is being edited or corrected. The driver edit limitation found in section 4.3.2.8.2(b) prohibits the editing of automatically recorded driving time. The intent of the specification that requires automatic recording of driving time is to ensure all movement of the CMV is captured.  A CMV cannot be driven while powered off.  The driving time following the power off cycle of a CMV not in motion, is not recorded to the specifications required by 4.3.1.2 and 4.4.1.1 and therefore may be edited to the correct duty status.

Last Updated : November 07, 2019

If the malfunction and/or event does not hinder the ELD’s accurate recording of the hours of service, the ELD rule does not require a documentation process. Under 49 CFR 395.34 drivers are still required to report a malfunction to a carrier within 24 hours and the motor carrier is required to repair or replace the malfunctioning ELD within 8 days. However, if the event does not affect hours of service and has been cleared by the ELD itself, the additional reporting requirements under 49 CFR 395.34 do not apply. In addition, drivers are required to follow any motor carrier instructions for diagnostic events and must review their records of duty status and certify they are true and correct under 49 CFR 395.30.  Motor carriers should continue to monitor such short-term diagnostic events and malfunctions to ensure the ELD is operating properly.

Last Updated : November 07, 2019

Engine synchronization in 4.2, for purposes of ELD compliance, is defined as the monitoring of the vehicle’s engine operation to automatically capture the engine’s power status, vehicle’s motion status, miles driven value, and engine hours value when the CMV’s engine is powered. As described in 4.3.1.1, the ELD must be powered and become fully functional within one minute of the vehicle’s engine receiving power and must remain powered for as long as the vehicle’s engine stays powered. Additionally, 4.5.1.6 allows up to one minute for the ELD to establish a link to the ECM or ECM connection and record all the required data elements during the power up event.  Therefore, during the power-up cycle, an ELD has one minute to establish the synchronization required by 4.2 and record the power up event. The specification is designed to capture when the CMV is put into a state where it can be driven. When the engine is not powered, the ELD does not have to capture data. An engine synchronization diagnostic event should not be recorded by the ELD during the power up cycle until one of the following occurs.

  • Five seconds elapses after the power up cycle is completed and recorded; or
  • Five seconds elapses after the ELD has not established a link to the ECM or ECM connection within one minute of the engine receiving power. 

Last Updated : November 07, 2019