U3000:47

Diagnostic Routine AE

Diagnostic Overview

C1B14:11, 12 or U3000:47

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

Normal Operation and Fault Conditions

The brake booster vacuum sensor measures the amount of vacuum in the brake booster as compared to the atmosphere. This information is sent to the ABS (Anti-Lock Brake System) module and is used to determine if additional braking assistance is required. A vacuum leak, a circuit failure in the sensor wiring, a brake booster with a mechanical failure or an internal failure of the vacuum sensor or ABS (Anti-Lock Brake System) module results in a DTC (Diagnostic Trouble Code) being set in the ABS (Anti-Lock Brake System) module. REFER to Brake Booster Vacuum Sensor .

DTC Fault Trigger Conditions






Pinpoint Test

1. CHECK FOR ABS (Anti-Lock Brake System) MODULE SYSTEM VOLTAGE DTCs (Diagnostic Trouble Codes)

1. Ignition ON.

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

Is DTC (Diagnostic Trouble Code) U3003:16 or U3003:17 present?






2. CHECK THE ABS (Anti-Lock Brake System) MODULE SUPPLY VOLTAGE (VPWR_ABS) PID (Parameter Identification)

1. Ignition ON.

2. Measure and record the voltage at the battery.

3. Using a scan tool, monitor the VPWR_ABS PID (Parameter Identification).

Is the PID (Parameter Identification) display within 0.2 volt of the recorded battery voltage?






3. CHECK THE ABS (Anti-Lock Brake System) MODULE VOLTAGE SUPPLY

1. Ignition OFF.

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

3. Ignition ON.

4. Measure:





Is each voltage within 0.2 volt of the recorded battery voltage?






4. CHECK THE ABS (Anti-Lock Brake System) MODULE GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect the battery negative cable. REFER to Battery Disconnect .

3. Measure:





Is the resistance less than 3 ohms?






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

1. Inspect the ABS (Anti-Lock Brake System) Module electrical connector (if not previously disconnected).

2. 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

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

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

Is the concern still present?