OBD-II Code P1380 — What It Means & How to Fix It

What Does This Error Mean?

P1380 appears on GM and some Oldsmobile vehicles to indicate that the ABS module has detected rough road conditions that are interfering with misfire detection. The PCM uses the ABS wheel speed sensors to detect engine misfires. If the ABS module signals that the road surface is too rough, the PCM disables misfire detection to avoid false misfire codes. P1380 is set as an informational code to indicate this has occurred. It is not a critical fault by itself.

Affected Models

Common in Chevrolet Malibu and Impala with ABS-enhanced misfire detection
Common in Pontiac Grand Am and Grand Prix
Common in Oldsmobile Alero and Cutlass Supreme
Common in Buick Century and Regal

Common Causes

Driving on rough road surfaces causing the ABS module to disable misfire detection
Faulty ABS wheel speed sensor sending false rough-road signals to the ABS module
Wiring fault in the ABS communication circuit to the PCM
ABS module fault causing incorrect rough-road status messages
Loose or corroded ABS tone ring causing erratic wheel speed sensor readings

How to Fix It

Note whether P1380 appeared while driving on rough or unpaved roads. If so, this is likely normal system behavior.

P1380 is expected to appear and clear on its own after returning to smooth road driving.
Check for any ABS warning lights on the dashboard. If the ABS light is on alongside P1380, the ABS system needs diagnosis.

An ABS fault that causes constant rough-road signals will prevent misfire detection from ever running.
Connect a scan tool and check for companion ABS codes. These will point to which wheel speed sensor or ABS component is faulty.

ABS codes store separately from powertrain codes on GM vehicles.
Inspect each ABS wheel speed sensor and its tone ring for damage, debris, or corrosion.

Metal shavings from brake dust can accumulate on the tone ring and cause false rough-road signals.
If an ABS sensor is faulty, replace it. Clear all codes and test drive on smooth road to confirm P1380 does not return.

After ABS repair, misfire detection will resume normal operation.

When to Call a Professional

P1380 alone is not urgent. However, if it appears with ABS warning lights, have the ABS system inspected. ABS wheel speed sensor replacement is $80 to $200 per sensor. ABS module diagnosis and replacement can cost $300 to $800 at a shop.

Frequently Asked Questions

Is P1380 a serious code I need to fix right away?

On its own, P1380 is usually not urgent. It is an informational code that tells you misfire detection was temporarily suspended. However, if it appears with ABS warning lights, the ABS system needs attention.

Why does the PCM use ABS sensors to detect misfires?

GM uses a clever system where engine misfires cause tiny but measurable changes in wheel speed. The PCM monitors these changes through the ABS sensors to confirm a misfire occurred. Rough roads create wheel speed variations that look like misfire events, so the system pauses detection to avoid false codes.

Can P1380 cause me to miss an actual misfire?

Yes, temporarily. While P1380 is active, misfire detection is suspended. Real misfires during this time would not set a misfire code. This is by design — it prevents false misfire codes from rough roads. Once smooth roads resume, detection turns back on automatically.