Code Details
| Display code | ELD Engine Synchronization Malfunction |
|---|---|
| SPN | Not applicable or not verified |
| FMI | Not applicable or not verified |
| OEM code | None listed |
| Manufacturer | FMCSA |
| System | Electronic Logging Device |
| Component | Engine ECM data connection |
| Source address | Unknown or not applicable |
| Severity | medium |
| Review status | ai source checked |
| Source confidence | high |
| Last reviewed | 2026-05-05 |
Plain-English Meaning
The ELD depends on vehicle data to automatically record driving activity. If it cannot obtain required values when needed, it may show a data diagnostic event or a malfunction depending on duration and severity.
FMCSA guidance links this category to loss of connectivity with required engine ECM data sources and inability to acquire updated required ELD parameters within the required timing window.
Common Symptoms
- Engine synchronization diagnostic message
- ELD cannot read odometer or engine hours
- Automatic driving status may not record normally
- Unidentified driving records may appear
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- ELD-to-databus connection may be loose or misconfigured
- Vehicle ECM data may not be available to the ELD
- Incorrect vehicle profile or device cable may be used
- ELD hardware, app, or firmware may need provider support
First Checks
- Confirm whether the ELD is showing a malfunction indicator, a data diagnostic indicator, or both.
- Record the displayed category, event time, vehicle, driver, and any related messages before clearing anything.
- Follow the motor carrier's and ELD provider's instructions for data diagnostic events.
- For malfunctions, notify the carrier and verify recordkeeping steps against current FMCSA requirements.
Can I Keep Driving?
The truck may still operate normally, but the ELD record may be noncompliant or incomplete. Follow carrier and ELD provider instructions promptly.
Related Codes
Related Lookup Pages
Sources
- ELD Malfunctions and Data Diagnostic Events Federal Motor Carrier Safety Administration · government · accessed 2026-05-05 · confidence high
Source: Federal Motor Carrier Safety Administration, ELD Malfunctions and Data Diagnostic Events. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - 49 CFR 395.34 - ELD malfunctions and data diagnostic events Electronic Code of Federal Regulations · government · accessed 2026-05-05 · confidence high
Source: Electronic Code of Federal Regulations, 49 CFR 395.34 - ELD malfunctions and data diagnostic events. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - 49 CFR Part 395 Appendix A to Subpart B - Functional Specifications for ELDs Electronic Code of Federal Regulations · government · accessed 2026-05-05 · confidence high
Source: Electronic Code of Federal Regulations, 49 CFR Part 395 Appendix A to Subpart B - Functional Specifications for ELDs. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
Is a engine synchronization malfunction the same as an engine fault code?
No. ELD malfunction and data diagnostic categories relate to electronic logging compliance and recorded hours-of-service data. They may involve vehicle data, but they are not the same thing as an engine ECM DTC.
Can this page replace the ELD provider's instructions?
No. ELD products vary, and the provider's instructions and the motor carrier's procedures should be used for the specific device.
Should a driver ignore an ELD data diagnostic event?
No. A data diagnostic event signals a data inconsistency. FMCSA guidance says the driver should follow the motor carrier's and ELD provider's recommendations to resolve it.