Diesel Data: Automotive Repair

P15B5

DTC P15B5: Brake Fluid Pressure Sensor B Signal Malfunction

1. Turn the ignition switch ON (II).
2. Check the BRAKE FLUID PRESSURE SENSOR B with the HDS without pressing the brake pedal.

Is there 2.45 MPa or more?

YES - Go to step 3.

NO - The system is OK at this time. Check for poor connections or loose terminals at brake fluid pressure sensor B and the ECM.

3. Turn the ignition switch OFF.
4. Disconnect the brake fluid pressure sensor B 3P connector.
5. Turn the ignition switch ON (II).




6. Measure voltage between brake fluid pressure sensor B 3P connector terminals No.1 and No.2.

Is there about 5.0 V?

YES - Replace brake fluid pressure sensor B.

NO - Go to step 7.

7. Turn the ignition switch OFF.
8. Disconnect ECM connector C (31P).




9. Connect ECM connector terminal C2 to body ground with a jumper wire.




10. Check for continuity between brake fluid pressure sensor B 3P connector terminal No.1 and body ground.

Is there continuity?

YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.

NO - Repair open in the wire between brake fluid pressure sensor B and the ECM (C2).