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Home >> Ford >> 2002 >> Taurus SES, 3.0 S >> Repair and Diagnosis >> External Pages >> Different car >> Section 194 (Engine Controls - Self-Diagnostics - 6.0L (99P F450/550) Diesel) >> System Tests >> Test Ai: Brake Lamp Switch >> Testing

Test Ai: Brake Lamp Switch: Testing

WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: The Powertrain Control Module (PCM) harness connectors must be properly seated and the connector latch properly attached to eliminate possible driveability concerns or a no-start condition. Installing PCM connectors on an angle may cause a bad connection, misdiagnosis and damaged components. Install the connector on where the lever pivots and seats itself. Apply light pressure to get the connector into position on the PCM lever to fully seat the connector.
NOTE: When the PCM engine harness connector is disconnected additional DTCs will be set. All DTCs must be cleared before returning the vehicle to service.
NOTE: DTC P1703 indicates that during KOEO Self-Test the BPP signal was high or during Key On Engine Running KOER Self-Test the BPP signal did not cycle.

  1. 1) DTC P0703 OR P1703

    Key on, engine off. Using scan tool, access the BPP PID. Does the BPP PID indicate ON? If yes, go to next step. If no, go to step  4).

  2. 2) Check The BPP Switch

    Key off. Disconnect the BPP switch. Key on, engine off. Access the BPP PID. Does the BPP PID indicate ON? If yes, go to next step. If no, install a new brake lamp switch.

  3. 3) Check The BPP Switch Input Circuit For A Short To Voltage

    Key off. Disconnect the PCM. Key on, engine off. Measure the voltage between the BPP switch input circuit terminal No. 2, harness side and ground. See Figure. Is any voltage indicated? If yes, repair the circuit. If no, install a new PCM.

  4. 4) Check The BPP Switch Operation

    Press and hold the brake pedal. Release the brake pedal. Does the BPP PID indicate ON then OFF? If yes, fault may be intermittent. Go to step  12). If no, go to next step.

  5. 6) Check The BPP Switch For Voltage

    Key off. Disconnect the BPP switch. Measure the voltage between the BPP switch B+ circuit terminal No. 3, harness side and ground. See Figure. Is the voltage greater than 10 volts? If yes, go to next step. If no, repair the circuit.

  6. 7) Check The BPP Switch

    Key on, engine off. Using scan tool, access the BPP PID. Connect a fused jumper (5-amp) between the BPP switch B+ circuit terminal No. 3, harness side and the BPP switch input circuit terminal No. 2, harness side. Does the BPP PID indicate ON? If yes, install a new BPP switch. If no, go to next step.

  7. 8) Check The BPP Switch Input Circuit For An Open

    Key off. Disconnect the PCM. Measure the resistance between the BPP switch input circuit terminal No. 2, harness side and the PCM body connector C1381A terminal No. 18, harness side. See CONTROL MODULE CONNECTOR IDENTIFICATION . Is the resistance less than 5 ohms? If yes, install a new PCM. If no, repair open circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 8) to step 12). No test procedures have been omitted.

  8. 12) Check For Intermittent Circuit Fault

    Key on, engine off. Using scan tool, access the BPP PID. Wiggle the connector and wiring while observing the BPP PID. Does the BPP PID indicate ON and OFF? If yes, repair the circuit as necessary. If no, the system is operating correctly.
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