C122D

C122D - ACTIVE BRAKE BOOSTER CONTROL CIRCUIT






For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
With the ignition on.

- Set Condition:
When the Anti-Lock Brake Module indicates that the Active Brake Booster voltage is out of range.






1. CHECK FOR A DTC C122D ACTIVE BRAKE BOOSTER CONTROL CIRCUIT

NOTE: This DTC must be active for the results of this test to be valid.

1. Turn the ignition on.
2. With the scan tool, read and record DTCs.
3. With the scan tool, read and record Freeze Frame information.
4. With the scan tool, erase DTCs.
5. Start the engine.
6. Depress and release the brake pedal.
7. With the scan tool, read and record DTCs.

Does the scan tool display: C122D ACTIVE BRAKE BOOSTER CONTROL CIRCUIT?

Yes
- Go To 2

No
- Refer to the INTERMITTENT CONDITION diagnostic procedure.
- Perform ABS VERIFICATION TEST - VER 1.

2. CHECK THE TERMINALS/CONNECTORS/WIRING HARNESS FOR DAMAGE

1. Turn the ignition off.
2. Check all related wiring for bruised, chafed, pierced, or partially broken wires.
3. Check all related connectors for broken, bent, pushed out, or corroded terminals.

Were any problems found?

Yes
- Repair as necessary.
- Perform ABS VERIFICATION TEST - VER 1.

No
- Go To 3

3.(B131) ACTIVE BRAKE BOOSTER (+) CIRCUIT






NOTE: Make sure the Battery is in good condition. Using the Midtronics Battery Tester, test the Battery before continuing.

1. Disconnect the Active Brake Booster harness connector.
2. Turn ignition on.
3. Using a voltmeter, measure the voltage of (B131) Active Brake Booster (+) circuit at the Active Brake Booster harness connector.

Is the voltage above 10 volts?

Yes
- Go To 4

No
- Repair the (B131) Active Brake Booster (+) circuit for an open or short to ground.
- Perform ABS VERIFICATION TEST - VER 1.

4.ACTIVE BRAKE BOOSTER SOLENOID

1. Turn ignition off.
2. At the Active Brake Booster Solenoid, measure the resistance from (B131) Active Brake Booster (+) to (B132) Active Brake Booster (-).

Is the resistance between 2.0 and 4.0 ohms?

Yes
- Go To 5

No
- Replace the Active Brake Booster Solenoid.
- Perform ABS VERIFICATION TEST - VER 1.

5.(B132) ACTIVE BRAKE BOOSTER (-) SHORT TO VOLTAGE






1. Disconnect the Anti-Lock Brake Module harness connector.
2. Turn ignition on.
3. Using a voltmeter, measure the voltage of (B132) Active Brake Booster (-) circuit at the Active Brake Booster harness connector.

Is voltage present?

Yes
- Repair the (B132) Active Brake Booster (-) circuit for an short to voltage.
- Perform ABS VERIFICATION TEST - VER 1.

No
- Go To 6

6.(B132) ACTIVE BRAKE BOOSTER (-) CIRCUIT SHORT TO GROUND






1. Turn the ignition off.
2. Measure the resistance of the (B132) Active Brake Booster (-) circuit from the Active Brake Booster harness connector to ground.

Is there continuity?

Yes
- Repair the (B132) Active Brake Booster (-) circuit for an short to ground.
- Perform ABS VERIFICATION TEST - VER 1.

No
- Go To 7

7.(B132) ACTIVE BRAKE BOOSTER (-) CIRCUIT OPEN






1. Disconnect the Anti-Lock Module harness connector.
2. Measure the resistance of the (B132) Active Brake Booster (-) circuit from the Active Brake Booster harness connector to the Anti-Lock Brake Module harness connector.

Is the resistance below 5.0 ohms?

Yes
- Go To 8

No
- Repair the (B132) Active Brake Booster (-) circuit for an open.
- Perform ABS VERIFICATION TEST - VER 1.

8. ANTI-LOCK BRAKE MODULE

NOTE: Before continuing, check the ABM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

1. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes
- Repair as necessary.
- Perform ABS VERIFICATION TEST - VER 1.

No
- Replace and program the Anti-Lock Brake Module per Service Information.
- Perform ABS VERIFICATION TEST - VER 1.