C101A:2F

Diagnostic Routine Q

Diagnostic Overview

C101A:1C, 2A, 2F or 62

Refer to Wiring Diagram Set 42 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The brake booster vacuum pressure sensor receives a sensor supply voltage of 5 volts from the ABS (Anti-Lock Brake System) module. The sensor is also grounded through the ABS (Anti-Lock Brake System) module. The sensor uses the pressure differential between the atmosphere and the brake booster vacuum chamber to produce a return voltage signal to the ABS (Anti-Lock Brake System) module that is between 0.2 volt and 4.9 volts. The ABS (Anti-Lock Brake System) module uses other sensor inputs such as wheel speed, brake pedal and stability sensors to determine if the vehicle is stopping and at what rate of deceleration. This information is compared against the vacuum pressure sensor to determine the validity of the sensor signal and the working condition of the sensor itself.

DTC Fault Trigger Conditions






Visual Inspection and Diagnostic Pre-checks

- Inspect the brake booster for vacuum leaks.

- Inspect the brake booster for any obvious signs of damage.

- Inspect the brake booster vacuum sensor harness and connector of any obvious signs of damage.

- Make sure the brake booster vacuum sensor electrical connector is free from any corrosion or other contaminants.

Pinpoint Test

1. CHECK THE DTCs (Diagnostic Trouble Codes) FROM THE ABS (Anti-Lock Brake System) MODULE

1. Ignition ON.

2. Using a scan tool, carry out the ABS (Anti-Lock Brake System) module self-test.

Is DTC (Diagnostic Trouble Code) C1B14:11, 12 or U3000:47 present?






2. CHECK THE BRAKE BOOSTER AND VACUUM HOSES FOR LEAKS

1. Inspect the vacuum hoses, brake booster and brake booster seals for leaks or evidence of leaks.

Are any leaks or evidence of leaks found?






3. CHECK THE VACUUM SENSOR WIRING FOR A SHORT TO VOLTAGE

1. Ignition OFF.

2. Disconnect ABS (Anti-Lock Brake System) Module electrical connector.

3. Disconnect Brake Booster Vacuum Sensor electrical connector.

4. Ignition ON.

5. Measure:





Is any voltage present?






4. CHECK THE VACUUM SENSOR WIRING FOR A SHORT TO GROUND

1. Ignition OFF.

2. Measure:





Are the resistances greater than 10,000 ohms?






5. CHECK THE VACUUM SENSOR WIRING FOR AN OPEN

1. Measure:





Are the resistances less than 3 ohms?






6. CHECK THE VACUUM SENSOR WIRING FOR A SHORT TOGETHER

1. Measure:





Are the resistances greater than 10,000 ohms?






7. CHECK FOR CORRECT ABS (Anti-Lock Brake System) MODULE OPERATION

1. Ignition OFF.

2. Disconnect and inspect the ABS (Anti-Lock Brake System) Module electrical connector.

3. Repair:

- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

4. Connect the ABS (Anti-Lock Brake System) Module electrical connector. Make sure it seats and latches correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?