P1380
Misfire Detected — Rough Road Data Not Available
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The P1380 code is unique to GM vehicles and indicates a special situation: the PCM has detected a possible engine misfire but cannot confirm it because rough road data from the ABS system is not available. GM's misfire detection system relies on the ABS module to report when the vehicle is driving over rough roads, because road vibrations can mimic the crankshaft speed variations caused by actual misfires.
This code is often triggered by an ABS system problem rather than an engine problem. A faulty wheel speed sensor, a communication failure between the ABS module and PCM, or even a separate ABS code can prevent rough road data from reaching the PCM. However, there may also be a genuine misfire present that needs attention.
Diagnosis should start by checking for any ABS-related codes stored alongside P1380. If ABS codes are present, address those first. If the ABS system checks out, then investigate the engine for misfire causes such as worn spark plugs, bad ignition coils, or fuel delivery issues. This code alone is not dangerous to drive with, but the underlying ABS or misfire issue should be investigated.
Severity
Symptoms
- •Check engine light is on
- •Engine may feel rough or vibrate during driving
- •Slight hesitation or stumble during acceleration
- •May notice reduced fuel economy
- •ABS or traction control warning light may also be on
Likely Causes
The Electronic Brake Control Module (EBCM) is unable to send rough road data to the PCM. The PCM needs this data to distinguish real misfires from vibrations caused by rough roads. An ABS module fault or communication issue is the most common trigger.
The EBCM uses wheel speed sensor data to detect rough road conditions. A failed or intermittent wheel speed sensor prevents the EBCM from generating accurate rough road data.
A genuine misfire from worn spark plugs, bad coils, or clogged fuel injectors is occurring simultaneously with the loss of rough road data from the ABS system.
The serial data communication line between the ABS module and the PCM may be damaged, corroded, or have a loose connection.
The ABS module itself has an internal fault preventing it from processing or transmitting rough road information to the PCM.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Diagnose and repair ABS system communication issues
- Replace a faulty wheel speed sensor
- Inspect and repair wiring between the EBCM and PCM
- Replace spark plugs, ignition coils, or fuel injectors if a genuine misfire is present
- Reprogram or replace the EBCM if it has an internal fault