P1380

DTC P1380 ABS Rough Road System Fault




Circuit Description
The PCM identifies an engine misfire by detecting the variations in crankshaft speed. The crankshaft speed variations can also occur when a vehicle is operated over a rough surface. The ABS (Anti-Lock Brake System) can detect when the vehicle is on a rough surface based on the wheel acceleration/deceleration data supplied by each wheel speed sensor. The EBCM (Electronic Brake Control Module) over the Class 2 serial data line sends this information to the PCM. The 0CM then uses this information in order to determine if the crankshaft variations are being caused by an actual engine misfire or from being driven on a rough surface.

This Diagnostic determines if the ABS system is not capable of detecting a rough road situation. DTC P1380 is a type D code.

Conditions for Setting the DTC
- 20 unusable ABS data values within a 50 value sample.

Conditions for Clearing the DTC
- A history DTC clears after 40 consecutive warm-up cycles without a fault.
- The Tech 2 can clear the DTC.

Diagnostic Aids
The setting of this DTC indicates that a misfire was detected and that the PCM could not determine if the detected misfire was true or due to operating the vehicle on a rough surface. A misfire can be a true misfire with or without setting this DTC. Check the EBCM for poor connections at the Class 2 serial data terminals. Be sure no true misfire exists after repairing the cause of this DTC.

Steps 1 - 2:

Steps 3 - 9:

Step 10:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart:
1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the Tech 2 is applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the Tech 2 for later reference.
2. ABS DTCs are found by selecting Chassis on the Tech 2.
3. Be careful to clear only DTCs and not the captured information stored on the Tech 2. The Tech 2 will issue a warning if this is about to happen.
4. A DTC P1380 being reset indicated that the PCM is not receiving the correct information from the EBCM due to an ABS DTC.
5. When DTC P1380 is set, and ABS DTC should also be set.
6. Refer to Anti-lock Brake System of the service manual for ABS DTCs and repairs.
8. Repair any condition that remains and is causing a misfire by following the table for any DTC that has set.
9. Replacement PCMs must be reprogrammed. Refer to the latest Isuzu Technical Communication System information for programming procedures.