Antilock Brake System (ABS): 1212
1212 - CAB SYSTEM OVERVOLTAGE
When Monitored and Set Condition
- When Monitored: Ignition on. The Controller Antilock Brake (CAB) monitors the Fused B(+) circuit at all times for proper system voltage.
- Set Condition: If the voltage is above 16 volts for greater than 500 milliseconds (ms), the Diagnostic Trouble Code (DTC) is set.
For a complete Antilock Brake System (ABS) Circuit Diagram Refer to BRAKES - SCHEMATICS And DIAGRAMS Schematics And Diagrams.
Diagnostic Test
1. WITH THE DRB III(R), READ DTCs
Turn the ignition on.
With the DRB III(R), erase DTCs.
Turn the ignition off.
Turn the ignition on.
Start the engine.
With the DRB III(R), read DTCs.
Does the DRB III(R) display a System Overvoltage DTC?
Yes
- Go to 2
No
- The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.
2. MEASURE THE BATTERY VOLTAGE
Start the engine.
Raise engine speed above 1,800 RPM.
Measure the battery voltage.
Is the voltage above 16 volts?
Yes
- Refer to the appropriate service information for charging system testing and repair.
- Perform ABS Verification Test. ABS Verification Test
No
- Go to 3
3. MEASURE THE RESISTANCE OF THE GROUND CIRCUIT
Turn the ignition off.
Disconnect the CAB connector.
NOTE: Check connector - Clean/repair as necessary.
Measure the resistance between ground and the Ground circuit at the CAB harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go to 4
No
- Repair the Ground circuit for an open.
- Perform ABS Verification Test. ABS Verification Test
4. MEASURE THE RESISTANCE OF THE GROUND CIRCUIT
With the ignition off.
Measure the resistance between ground and the Ground circuit at of 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 Ground circuit for an open.
- Perform ABS Verification Test. ABS Verification Test