Antilock Brake System (ABS): 1140

1140-ESP BRAKE PRESSURE SENSOR 1 CIRCUIT





When Monitored and Set Condition
^ When Monitored: ignition on.
^ Set Condition: The Controller Antilock Brake (CAB) detects an Electronic Stability Program (ESP) Brake Pressure Sensor 1 malfunction.

POSSIBLE CAUSES
- BRAKE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
- BRAKE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO 5-VOLT SUPPLY CIRCUIT
- BRAKE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND
- BRAKE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO SENSOR GROUND CIRCUIT
- BRAKE PRESSURE SENSOR SIGNAL CIRCUIT OPEN
- BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT SHORT TO VOLTAGE
- BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT OPEN
- BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
- BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT SHORT TO SENSOR GROUND
- BRAKE PRESSURE SENSOR GROUND CIRCUIT OPEN
- BRAKE PRESSURE SENSOR
- CONTROLLER ANTILOCK BRAKE (CAB)

For a complete Antilock Brake System (ABS) Circuit Diagram, (Refer to - BRAKES/ELECTRICAL - SCHEMATICS AND DIAGRAMS).

Diagnostic Test
1. MEASURE THE VOLTAGE OF THE ESP BRAKE PRESSURE SENSOR 1 SIGNAL CIRCUIT





Turn the ignition off. Disconnect the CAB harness connector. Disconnect the ESP Brake Pressure Sensor 1 harness connector.

Note: Check connectors -Clean/repair as necessary. Turn the ignition on. Measure the voltage of the ESP Brake Pressure Sensor 1 Signal circuit at the ESP Brake Pressure Sensor 1 harness connector.

Is the voltage below 1.0 volt?
Yes >> Go to 2
No >> Repair the ESP Brake Pressure Sensor 1 Signal circuit for a short to voltage. Perform ABS VERIFICATION TEST. ABS Verification Test

2. MEASURE THE RESISTANCE BETWEEN THE ESP BRAKE PRESSURE 1 SIGNAL CIRCUIT AND THE 5-VOLT SUPPLY CIRCUIT





Turn the ignition off.
Measure the resistance between the ESP Brake Pressure Sensor 1 Signal circuit and the 5-Volt Supply circuit in the ESP Brake Pressure Sensor 1 harness connector.
Is the resistance below 100k ohms?
Yes >> Repair the ESP Brake Pressure Sensor 1 Signal circuit for a short to the 5-Volt Supply circuit. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Go to 3

3. MEASURE THE RESISTANCE OF THE ESP BRAKE PRESSURE SENSOR 1 SIGNAL CIRCUIT





With the ignition off. Measure the resistance of the ESP Brake Pressure Sensor 1 Signal circuit from the CAB harness connector to the ESP Brake Pressure Sensor 1 harness connector.
Is the resistance below 5.0 ohms?
Yes >> Go to 4
No >> Repair the ESP Brake Pressure Sensor 1 Signal circuit for an open. Perform ABS VERIFICATION TEST. ABS Verification Test

4. MEASURE THE RESISTANCE OF THE ESP BRAKE PRESSURE SENSOR 1 GROUND CIRCUIT





With the ignition off. Measure the resistance of the Sensor Ground circuit from the CAB harness connector to the ESP Brake Pressure Sensor 1 harness connector.
Is the resistance below 5.0 ohms?
Yes >> Go to 5
No >> Repair the Sensor Ground circuit for an open. Perform ABS VERIFICATION TEST. ABS Verification Test

5. MEASURE THE VOLTAGE OF THE 5-VOLT SUPPLY CIRCUIT





With the ignition off. Reconnect the CAB harness connector. Turn the ignition on. Measure the voltage of the 5-Volt Supply circuit at the ESP Brake Pressure Sensor 1 harness connector.
Is the voltage between 4.5 and 5.0 volts?
Yes >> Go to 6
No >> Go to 8

6. MEASURE THE RESISTANCE BETWEEN GROUND AND THE ESP BRAKE PRESSURE SENSOR 1 SIGNAL CIRCUIT





Turn the ignition off. Disconnect the CAB harness connector.

Note: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the ESP Brake Pressure Sensor 1 Signal circuit.
Is the resistance below 100k ohms?
Yes >> Repair the ESP Brake Pressure Sensor 1 Signal circuit for a short to ground. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Go to 7

7. MEASURE THE RESISTANCE BETWEEN THE ESP BRAKE PRESSURE SENSOR 1 SIGNAL CIRCUIT AND THE SENSOR GROUND CIRCUIT





With the ignition off. Measure the resistance between the ESP Brake Pressure Sensor 1 Signal circuit and the Sensor Ground circuit in the ESP Brake Pressure Sensor 1 harness connector.
Is the resistance below 100k ohms?
Yes >> Repair the ESP Brake Pressure Sensor 1 Signal circuit for a short to the Sensor Ground circuit. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Replace the ESP Brake Pressure Sensor 1. Perform ABS VERIFICATION TEST. ABS Verification Test

8. CHECK THE ESP BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE





Turn the ignition off. Disconnect the CAB harness connector.

Note: Check connectors - Clean/repair as necessary.

Turn the ignition on. Measure the voltage of the 5-Volt Supply circuit at the ESP Brake Pressure Sensor 1 harness connector.
Is the voltage below 1.0 volt?
Yes >> Go to 9
No >> Repair the 5-Volt Supply circuit for a short to voltage. Perform ABS VERIFICATION TEST. ABS Verification Test

9. MEASURE THE RESISTANCE BETWEEN THE ESP BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT AND THE SENSOR GROUND CIRCUIT





Turn the ignition off.
Measure the resistance between the 5-Volt Supply circuit and the Sensor Ground circuit.
Is the resistance below 100k ohms?
Yes >> Repair the 5-Volt Supply circuit for a short to the Sensor Ground circuit. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Go to 10

10. MEASURE THE RESISTANCE BETWEEN GROUND AND THE ESP BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT





With the ignition off.
Measure the resistance between ground and the 5-Volt Supply circuit.
Is the resistance below 100k ohms?
Yes >> Repair the 5-Volt Supply circuit for a short to ground. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Go to 11

11. MEASURE THE RESISTANCE OF THE ESP BRAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT





With the ignition off.
Measure the resistance of the 5-Volt Supply circuit from the ESP Brake Pressure Sensor 1 harness connector to the CAB harness connector.
Is the resistance below 5.0 ohms?
Yes >> Replace the Controller Antilock Brake (CAB) Module. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Repair the ESP Brake Pressure Sensor 5-Volt Supply circuit for an open. Perform ABS VERIFICATION TEST. ABS Verification Test