ELD Malfunction Codes 2026: 13 Codes and What to Do
Every registered ELD has to watch itself for problems and tell the driver when something goes wrong. It does that with a standard set of codes defined in Appendix A to Subpart B of 49 CFR Part 395. There are 7 malfunction codes, shown with letters, and 6 data diagnostic codes, shown with numbers. They look the same whichever brand you run, from Motive to Garmin.
The difference between the two matters. A data diagnostic event is a warning that some data may be missing or wrong. A malfunction means the device is not working as a compliant ELD, and you have to switch to paper logs. Here is the full list.
The 7 Malfunction Codes
| Code | Malfunction | What usually causes it |
|---|---|---|
| P | Power compliance | The ELD lost power long enough to miss 30 minutes or more of driving time in a 24 hour period |
| E | Engine synchronization | The ELD could not get engine data such as speed, miles or engine hours for 30 minutes or more in a 24 hour period |
| T | Timing compliance | The device clock drifted more than 10 minutes from UTC |
| L | Positioning compliance | No valid GPS position for 60 minutes or more of driving in a 24 hour period |
| R | Data recording compliance | The ELD ran out of storage or cannot save or retrieve records |
| S | Data transfer compliance | The routine self check of the transfer function failed and stayed failed |
| O | Other | Any other malfunction the provider has defined and documented |
The 6 Data Diagnostic Codes
| Code | Data diagnostic event | What it means |
|---|---|---|
| 1 | Power data diagnostic | The ELD was not powered and ready within 1 minute of the engine turning on |
| 2 | Engine synchronization data diagnostic | The ELD lost its connection to the engine computer for more than 5 seconds |
| 3 | Missing required data elements | A record is missing a required item, often location |
| 4 | Data transfer data diagnostic | A data transfer check failed once |
| 5 | Unidentified driving records | More than 30 minutes of unassigned driving in a 24 hour period |
| 6 | Other | Any other diagnostic the provider defines |
Code 5 is the one most fleets see. Our guide to unidentified driving records explains how to clear it by assigning or annotating the driving time.
What the Driver Must Do After a Malfunction
Under 49 CFR 395.34, a driver whose ELD malfunctions has three jobs:
- Note the malfunction and give the carrier written notice within 24 hours.
- Rebuild the record of duty status for the current 24 hour period and the previous 7 days on paper graph grid logs, unless the records can be pulled from the ELD.
- Keep logging on paper until the ELD is repaired or replaced.
That is why the rules require 8 days of blank paper logs in the cab. If an officer stops you while the device is down, show the paper logs and the malfunction instruction sheet.
What the Carrier Must Do
The carrier has 8 days from when it finds out, or from the driver's notice, to repair, replace or service the ELD. If that is not possible, the carrier can ask its FMCSA Division Administrator for an extension within 5 days of the driver's notice. In practice most fleets keep a spare device or cable on hand, since a replacement usually ships faster than an extension request is answered.
| Who | Deadline | Action |
|---|---|---|
| Driver | 24 hours | Written notice to the carrier |
| Driver | Immediately | Paper logs for today and the previous 7 days |
| Carrier | 8 days | Repair or replace the ELD |
| Carrier | 5 days from notice | Request an extension if needed |
Quick Fixes Worth Trying First
- E and 2 codes: Reseat the cable at the diagnostic port and check for a bent pin. Loose connectors cause more engine sync faults than anything else.
- L and 3 codes: Turn on location services and check the tablet has a clear view of the sky. Some phones save battery by cutting GPS.
- T codes: Set the device to update its time automatically, then restart.
- S and 4 codes: Check the data connection, then run a test transfer. See our ELD data transfer guide.
- P and 1 codes: Check the fuse and power lead, and keep the tablet charged.
If a code keeps coming back, treat it as a hardware problem. Repeated malfunctions are also worth weighing when you renew a contract. Our best ELD guide and ELD tablet list can help you find steadier hardware.
Codes and Roadside Inspections
A cleared data diagnostic is not a violation on its own. An active malfunction with no paper logs is. Officers look for the indicator, then ask for the paper record. Keep the malfunction instruction sheet, the user manual and the data transfer sheet in the cab, as 395.22(h) requires. Fleets that handle this well rarely get more than a warning.
Frequently Asked Questions
What is the difference between an ELD malfunction and a data diagnostic?
A data diagnostic is a warning about possibly missing or inconsistent data. A malfunction means the ELD is not working as a compliant device, so the driver must switch to paper logs.
How long can I drive on paper logs after an ELD malfunction?
Up to 8 days, the time the carrier has to repair or replace the device, unless FMCSA grants an extension.
What does malfunction code E mean?
Engine synchronization. The ELD could not get required engine data for 30 minutes or more in a 24 hour period.
Sources
- 49 CFR Part 395 Subpart B, Appendix A, sections 4.6 and Table 4, eCFR, checked October 2026.
- 49 CFR 395.34 ELD malfunctions and data diagnostic events, eCFR, checked October 2026.
- 49 CFR 395.22(h) driver documents, eCFR, checked October 2026.
- FMCSA ELD frequently asked questions, eld.fmcsa.dot.gov, checked October 2026.