The P1380 diagnostic trouble code is a manufacturer-specific powertrain code. Its exact definition depends heavily on the vehicle make, pointing to a rough road data communication fault, a variable cam timing circuit issue, or a glow plug relay malfunction.
Because this code targets entirely different systems across manufacturers, the exact vehicle application must be verified before diagnosis. The code alone does not prove a specific component has failed without proper testing.
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Key Takeaways
- P1380 is a manufacturer-specific powertrain code with differing definitions depending on the vehicle make.
- On GM applications, it indicates a Misfire Detected but Rough Road Data Not Available from the ABS module.
- On Ford applications, it points to a Variable Cam Timing (VCT) Solenoid Valve Circuit Short or Open.
- On Honda and Acura applications, it indicates a Cylinder Position (CYP) Sensor Intermittent Interruption.
- On VW, Audi, and Subaru diesel applications, it indicates a Glow Plug Relay or Control Unit circuit fault.
P1380 Code Description and Implications
The P1380 code indicates that a control module has detected a specific fault within the misfire detection, valve timing, or diesel glow plug systems. Because it is a manufacturer-specific code, the exact monitored component varies significantly by brand.
Some GM applications: The Powertrain Control Module (PCM) detects a misfire condition but cannot communicate with the Electronic Brake Control Module (EBCM) to verify if the vibration is actually caused by a rough road surface.
Certain Ford applications: The PCM detects an electrical open or short circuit in the Variable Cam Timing (VCT) solenoid valve control circuit, preventing proper camshaft phasing.
Some Honda and Acura applications: The Engine Control Module (ECM) detects an intermittent signal drop or interruption from the Cylinder Position (CYP) sensor located inside the distributor.
Certain VW, Audi, and Subaru diesel applications: The engine control module detects an electrical fault, such as a short to positive voltage, in the glow plug relay or control unit circuit.
Common Causes of the P1380 Code
Because P1380 applies to different systems across different brands, the root cause depends on the verified vehicle application.
GM Causes: A communication failure between the PCM and the ABS/EBCM module, an ABS module internal fault, or damaged serial data communication wiring.
Ford Causes: A failing VCT solenoid, damaged wiring harness, poor electrical connections, or a blown fuse supplying the VCT circuit.
Honda and Acura Causes: A failing CYP sensor, damaged distributor wiring, or electromagnetic interference from carbon tracking inside a failing distributor cap.
VW, Audi, and Subaru Diesel Causes: A failing glow plug relay, damaged glow plug wiring harness, or a short circuit in the glow control unit.
Symptoms Associated With P1380
When the control module detects a critical system fault, it illuminates a warning light and may alter vehicle operation.
Warning Lights: The Check Engine Light will illuminate. On GM applications, a P0300 (Random Misfire) code often accompanies it. On diesel applications, a glowing coil warning light may flash.
Drivability: On GM applications, the engine may run normally, but the misfire monitor is disabled. On Ford applications, poor engine performance or a ticking noise may occur. On diesel applications, hard cold starting or white smoke may be present.
Diagnosing the P1380 Trouble Code
Accurate diagnosis begins by verifying the exact vehicle application and reviewing manufacturer-specific service information.
For GM applications: Check for ABS module communication codes. Verify the serial data communication circuit between the PCM and the EBCM for opens or shorts.
For Ford applications: Inspect the VCT solenoid wiring for opens or shorts to ground/voltage. Measure the solenoid resistance and compare it to manufacturer specifications.
For Honda and Acura applications: Inspect the distributor cap and rotor for carbon tracking. Test the CYP sensor signal and inspect the wiring connector for corrosion.
For VW, Audi, and Subaru diesel applications: Test the glow plug relay control and feedback circuits. Verify voltage supply to the glow plug harness.
Repairing the P1380 Issue
Repairs must follow the confirmed root cause identified during diagnosis.
Circuit and Module Repairs: If communication wiring is damaged on GM applications, repair the harness. If the ABS module fails internal diagnostics, follow the applicable module replacement procedure.
Solenoid Repairs: If the VCT solenoid fails resistance testing on Ford applications, replace the confirmed failed solenoid and clear the codes.
Sensor and Distributor Repairs: If the CYP sensor or distributor assembly fails testing on Honda applications, replace the confirmed failed components.
Relay and Wiring Repairs: If the glow plug relay or control unit fails testing on diesel applications, replace the relay and repair any damaged harness sections.
Cost Considerations for P1380 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing a VCT solenoid or a glow plug relay involves minimal to moderate labor. However, replacing an ABS module or a complete distributor assembly requires more extensive labor and potential module programming.
Prevention Strategies for Future Occurrences
Inspecting exposed wiring harnesses near the VCT solenoids and glow plug relays helps prevent short circuits caused by heat or chafing.
Keeping distributor caps and electrical connectors clean and secure helps prevent moisture intrusion and signal interruption on older Honda and Acura applications.
Troubleshooting Tips and Best Practices
Follow these practices to avoid misdiagnosis and ensure accurate repairs.
Do not replace the PCM or ABS module just because a rough road data code is present on GM applications: A simple wiring break or corroded connector in the data line is a frequent cause. Always verify the external wiring harness first.
Check for related codes: Look for accompanying ABS communication codes or specific misfire codes to help pinpoint the underlying system fault.
Verify your definition: Always confirm whether your specific vehicle uses the rough road, VCT, CYP sensor, or glow plug definition before ordering parts.
More OBD-II Codes
| P1360 | P1363 | P1364 | P1365 |
| P1366 | P1367 | P1381 | P1382 |
| P1386 | P1387 | P1388 | P1389 |
| P0300 | P0335 | P0340 | P1336 |
| P1404 | P1441 | P1546 | P1641 |
| P1651 | P1652 | P1655 | P1660 |
Frequently Asked Questions
Is P1380 a generic or manufacturer-specific code?
No. P1380 is a manufacturer-specific powertrain code. Its definition varies significantly by brand, indicating a rough road data fault, a variable cam timing issue, or a glow plug circuit malfunction.
Can I drive my vehicle with a P1380 code?
It depends on the application. On GM vehicles, it may drive normally but fail emissions testing. On Ford or diesel applications, drivability and cold starting may be severely impacted.
Will disconnecting the battery clear the P1380 code?
Disconnecting the battery might temporarily clear the code. However, it does not repair the underlying wiring break, failed sensor, or communication fault, and the code will return upon the next monitor cycle.
Can a bad ABS module cause a P1380 code on a GM vehicle?
Yes. The powertrain control module relies on the ABS module for rough road data. If the ABS module fails or loses communication, the powertrain module cannot verify misfires and sets P1380.
Does P1380 affect the transmission?
No. The P1380 code relates strictly to the engine misfire monitoring system, variable cam timing, cylinder position sensor, or diesel glow plug circuits. It does not directly affect transmission operation.
What Should You Do About the P1380 Code?
When a P1380 code appears, confirm the exact factory definition for your specific vehicle make and model. Because this code targets entirely different misfire monitoring, valve timing, and glow plug systems depending on the manufacturer, applying the wrong diagnostic path will lead to misdiagnosis.
Follow the applicable manufacturer diagnostic procedure to test the relevant system and components. Once the root cause is confirmed, complete the necessary electrical repairs, module replacements, or sensor corrections before returning the vehicle to normal service.
