Pinpoint Test K: DTC C1288 - BRAKE PRESSURE TRANSDUCER INPUT CIRCUIT FAILURE

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

K1 CHECK THE BRAKE PRESSURE TRANSDUCER CIRCUITRY FOR A SHORT TO VOLTAGE

Key in OFF position.
Disconnect: ABS Module C155.
Disconnect: Brake Pressure Transducer C147.
Key in ON position.

Measure the voltage between ABS module C155 pins, harness side and ground as follows:

ABS Module C155 Pin	Circuit
18	7-CF64 (YE/BK)
19	9-CF64 (BN/YE)
20	8-CF64 (WH/BK)

Is voltage present?

Yes : REPAIR the circuit in question. CLEAR the DTC. REPEAT the self-test.
No : GO to K2.

K2 CHECK THE BRAKE PRESSURE TRANSDUCER CIRCUITRY FOR A SHORT TO GROUND

Key in OFF position.

Measure the resistance between ABS module C155 pins, harness side and ground, as follows:

ABS Module C155 Pin	Circuit
18	7-CF64 (YE/BK)
19	9-CF64 (BN/YE)
20	8-CF64 (WH/BK)

Are the resistances greater than 10,000 ohms?

Yes : GO to K3.
No : REPAIR the circuit in question. CLEAR the DTC. REPEAT the self-test.

K3 CHECK THE BRAKE PRESSURE TRANSDUCER CIRCUITRY FOR AN OPEN

Measure the resistance between ABS module C155 pins, harness side and brake pressure transducer C147 pins, harness side as follows:

ABS Module C155 Pin	Brake Pressure Transducer C147 Pin	Circuit
19	1	9-CF64 (BN/YE)
20	2	8-CF64 (WH/BK)
18	3	7-CF64 (YE/BK)

Are the resistances less than 5 ohms?

Yes : GO to K4.
No : REPAIR the circuit in question. CLEAR the DTC. REPEAT the self-test.

K4 CHECK THE ABS MODULE OUTPUT
- Connect: ABS Module C155.
- Key in ON position.
- Measure the voltage between brake pressure transducer C147-3, circuit 7-CF64 (YE/BK), harness side and brake pressure transducer C147-1, circuit 9-CF64 (BN/YE), harness side.
  
  Fig 1: Measuring Voltage Between Brake Pressure Transducer C147-3, Circuit 7-CF64, Harness Side And Brake Pressure Transducer C147-1, Circuit 9-CF64, Harness Side
  Courtesy of FORD MOTOR CO.
- Is the voltage approximately 5 volts?
- Yes : GO to K5.
- No : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this article . REPEAT the self-test.
K5 CHECK THE BRAKE PRESSURE TRANSDUCER OUTPUT
- Connect: Brake Pressure Transducer C147.
- Disconnect: ABS Module C155.
- Remove the ABS module C155-20, circuit 8-CF64 (WH/BK) from the harness connector.
- Connect: ABS Module C155.
- Key in ON position.
- Measure the voltage between ABS module C155-20, with circuit 8-CF64 (WH/BK) removed from the harness connector and ground, while applying and releasing the brake pedal.
- Is the voltage between 0.125 and 0.375 volt with the brake pedal released and between 0.125 and 5 volts with the brake pedal applied?
- Yes : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this article . REPEAT the self-test.
- No : INSTALL a new brake booster. REFER to POWER BRAKE ACTUATION . CLEAR the DTC.
RECALIBRATE the ABS module. REPEAT the self-test.