Page 1178 of 4284

Symptom:
PUMP CIRCUIT FAILURE
When Monitored and Set Condition:
PUMP CIRCUIT FAILURE
When Monitored: Ignition on. The CAB commands the pump on at 20 km/h (12 mph) to
check its operation, if the brake switch is not applied. If the brake is applied, the test will
run at 40 km/h (25 mph). The CAB monitors pump voltage every 7 milliseconds.
Set Condition: The DTC is stored when the CAB detects: 1) Improper voltage decay after
the pump was turned off. 2) Pump not energized by the CAB, but voltage is present for 3.5
seconds. 3) Pump is turned on by the CAB, but without sufficient voltage to operate it.
POSSIBLE CAUSES
PUMP HARNESS DISCONNECTED
CAB - PUMP MOTOR RUNNING CONTINUOUSLY
ABS PUMP MOTOR INTERMITTENT DTC
GROUND CIRCUIT HIGH RESISTANCE
FUSED B(+) CIRCUIT OPEN
GROUND CIRCUIT OPEN
CAB - INTERNAL FAULT
CAB - SETTING FALSE CODE
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Turn the ignition on.
Monitor the pump motor for continuous operation.
Is the pump motor running continuously?All
Ye s®Replace the Controller Anti-Lock Brake in accordance with the
Service Information. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 2
2 Turn the ignition on.
With the DRBIIIt, read DTC's.
With the DRBIIIt, erase DTC's.
Turn the ignition off.
Turn the ignition on.
With the DRBIIIt, actuate the ABS pump motor.
Did the Pump Motor operate when actuated?All
Ye s®Go To 3
No®Go To 4
21
BRAKES (CAB)
Page 1179 of 4284

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?All
Ye s®Repair as necessary. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
No®Replace the Controller Anti-Lock Brake in accordance with the
Service Information. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
4 Check the short Wiring Harness between the ABS Pump and the CAB.
Check for disconnect and damage.
Is the harness disconnected or damaged?All
Ye s®Reconnect or repair the Pump Harness as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 5
5 Turn the ignition off.
Disconnect CAB Connector.
Note: Check connector - Clean/repair as necessary.
Measure the resistance of the CAB ground circuits.
Is the resistance below 1.0 ohm?All
Ye s®Go To 6
No®Repair the ground circuit for an open. The vehicle must be driven
at 25 km/h (15 mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
6 Turn the ignition on.
With the DRBIIIt, enable pump motor actuation.
NOTE: Pump motor will not operate, but voltage will be applied.
Measure the voltage drop across the ABS ground circuit connection, with pump motor
actuation enabled.
Is the voltage below 0.1 volt?All
Ye s®Go To 7
No®Repair the Ground circuit for high resistance. The vehicle must be
driven at 25 km/h (15 mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
22
BRAKES (CAB)
PUMP CIRCUIT FAILURE ÐContinued
Page 1180 of 4284
TEST ACTION APPLICABILITY
7 Turn the ignition off.
Disconnect the CAB connector.
Note: Check connector - Clean/repair as necessary.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Pump Motor Fused B+
circuit.
Does the test light illuminate brightly?All
Ye s®Go To 8
No®Repair the Fused B(+) circuit for an open. The vehicle must be
driven at 25 km/h (15 mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
8 If there are no possible causes remaining, view repair. All
Repair
Replace the Controller Anti-Lock Brake in accordance with the
Service Information. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
23
BRAKES (CAB)
PUMP CIRCUIT FAILURE ÐContinued
Page 1182 of 4284
TEST ACTION APPLICABILITY
3 With the DRBIIIt, read DTCs.
Did the DTC reoccur?All
Ye s®Replace the Controller Antilock Brake in accordance with the
Service Information. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 4
4 Turn the ignition off.
Visually inspect wheel speed sensor.
Visually inspect tone wheel.
Visually inspect wiring harness.
Visually inspect brakes for locking up due to lining contamination or overheating.
Inspect all Components for defects which may cause a Signal DTC to set.
Is any Component Damaged?All
Ye s®Repair as necessary. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
No®Test Complete.
25
BRAKES (CAB)
RIGHT FRONT WHEEL SPEED SIGNAL FAILURE ÐContinued
Page 1184 of 4284
TEST ACTION APPLICABILITY
3 With the DRBIIIt, read DTCs.
Did the DTC reoccur?All
Ye s®
No®Go To 4
4 Turn the ignition off.
Visually inspect wheel speed sensor.
Visually inspect tone wheel.
Visually inspect wiring harness.
Visually inspect brakes for locking up due to lining contamination or overheating.
Inspect all Components for defects which may cause a Signal DTC to set.
Is any Component Damaged?All
Ye s®Repair as necessary. The vehicle must be driven at 25 km/h (15
mph) to extinguish the ABS indicator.
Perform ABS VERIFICATION TEST - VER 1.
No®Test Complete.
27
BRAKES (CAB)
RIGHT REAR WHEEL SPEED SIGNAL FAILURE ÐContinued
Page 1186 of 4284

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the CAB connector.
Note: Check connector - Clean/repair as necessary.
Start the engine.
Raise engine speed above 1,800 RPM.
Measure the battery voltage.
Is the voltage above 16.5 volts ?All
Ye s®Refer to appropriate service information for charging system
testing and repair.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 4
4 Turn the ignition off.
Disconnect the CAB connector.
Note: Check connector - Clean/repair as necessary.
Measure the resistance of the ground circuits.
Is the resistance below 1.0 ohm?All
Ye s®Go To 5
No®Repair the Ground circuit for an open.
Perform ABS VERIFICATION TEST - VER 1.
5 If there are no potential causes remaining, view repair. All
Repair
Replace the Controller Antilock Brake.
Perform ABS VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?All
Ye s®Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No®Test Complete.
29
BRAKES (CAB)
SYSTEM OVERVOLTAGE ÐContinued
Page 1188 of 4284
TEST ACTION APPLICABILITY
4 If there are no potential causes remaining, view repair. All
Repair
Replace the Controller Antilock Brake.
Perform ABS VERIFICATION TEST - VER 1.
5 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?All
Ye s®Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No®Test Complete.
31
BRAKES (CAB)
SYSTEM UNDERVOLTAGE ÐContinued
Page 1190 of 4284

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Remove the ABS Fuse 21 from the IPM.
Disconnect the CAB harness connector.
Note: Check connector - Clean/repair as necessary.
Using a test light connected to 12 volts, probe the Fused B(+) Circuit.
Does the test light illuminate brightly?All
Ye s®Repair the Fused B(+) Circuit short to ground.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 4
4 Turn the ignition off.
Remove the ABS Fuse 21 from the IPM.
The CAB must be connected for the results of this test to be valid.
Using a test light connected to 12 volts, probe the Fused B(+) Circuit at the IPM fuse
terminal.
Does the test light illuminate brightly?All
Ye s®Replace the Controller Antilock Brake in accordance with the
Service Information.
Perform ABS VERIFICATION TEST - VER 1.
No®Go To 5
5 Turn the ignition off.
If there are no potential causes remaining, view repair.All
Continue
Replace the Fuse.
Perform ABS VERIFICATION TEST - VER 1.
6 Remove the ABS Fuse 21 from the IPM.
Turn the ignition on.
Measure the voltage of the Fused B+ supply to Fuse 21 in the IPM.
Is the voltage above 10 volts?All
Ye s®Go To 7
No®Repair the B+ Supply circuit for an open.
Perform ABS VERIFICATION TEST - VER 1.
7 Turn the ignition off.
Remove the ABS Fuse 21 from the IPM.
Disconnect the CAB harness connector.
Note: Check connector - Clean/repair as necessary.
Measure the resistance of the Fused B(+) circuit between IPM Fuse terminal 21 and
the CAB connector.
Is the resistance below 5 ohms?All
Ye s®Go To 8
No®Repair the Fuse B+ circuit for an open.
Perform ABS VERIFICATION TEST - VER 1.
8 If there are no possible causes remaining, view repair. All
Repair
Replace the Controller Antilock Brake in accordance with the
Service Information.
Perform ABS VERIFICATION TEST - VER 1.
33
BRAKES (CAB)
VALVE POWER FEED FAILURE ÐContinued