BigBore050

Ok so I change my front brake pads and had my rotors turned but when i did it I removed resivor cap and compressed the calipers w/ a c-clamp put everything back together. I drove the truck maybe 15 miles no problems then got back in the truck and the parking and abs light is on, I have no Anti-lock brakes, and once I got home and shut off the truck I can still hear the ABS Box humming after key is off. I had to disconect the abs to keep it from running.

I hunted down a ABS code reader (with the ABS box pluged in) it throws a 67 motor circit failure.

After talking to a mech he thought it is from pushing the brake fluid back through the system instead of opening the bleeder. and he said that maybe there is a way to undo what i did without going to the dealer.

so has anyone had this problem and found a way to fix it. or should I take it to the dealer with a can of vasoline

BigIron70

Diag procedure hope this helps.

PUMP MOTOR CIRCUIT OPEN - 67




For a complete wiring diagram Refer to Section 8W.

When Monitored:
Ignition on.

Set Condition:
Ignition on for at least 3.5 seconds. ABS pump motor command never given during the current ABS command. Low feedback voltage from the low side of the motor.

Possible Causes
ABS PUMP MOTOR INTERMITTENT DTC
FUSED B(+) CIRCUIT INTERMITTENTLY SHORTED TO GROUND
FUSED B(+) CIRCUIT SHORTED TO GROUND
FUSE OPEN - PUMP MOTOR CIRCUIT
NO B+ SUPPLY TO FUSE
ABS PUMP MOTOR INOPERATIVE
FUSED B(+) CIRCUIT OPEN
GROUND CIRCUIT OPEN
GROUND CIRCUIT HIGH RESISTANCE
CONTROLLER ANTI-LOCK BRAKE


Diagnostic Test
1. DTC IS ACTIVE

--------------------------------------------------------------------------------
Turn the ignition on.
With the scan tool, read DTC's.
With the scan tool, erase DTC's.
Turn the ignition off.
Turn the ignition on.
With the scan tool, actuate the ABS pump motor.

Did the Pump Motor operate when actuated?

Yes
Go To10

No
Go To2



2. FUSE OPEN - PUMP MOTOR CIRCUIT

--------------------------------------------------------------------------------
Turn the ignition off.
Remove and inspect the ABS Pump Motor fuse.

Is the Fuse open?

Yes
Go To3

No
Go To5



3. FUSED B(+) CIRCUIT INTERMITTENTLY SHORT

--------------------------------------------------------------------------------
Ensure the Pump Motor connector is secure.
Visually inspect the Fused B(+) circuit in the wiring harness from the ABS PUMP fuse to the CAB harness connector. Look for any signs of an intermittent short to ground.

Is the wiring harness OK?

Yes
Go To4

No
Repair as necessary.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



4. FUSED B(+) CIRCUIT SHORTED TO GROUND

--------------------------------------------------------------------------------
Disconnect the CAB harness connector.
Ensure the ABS Pump Motor connector is secure.
Measure the resistance of the Fused B(+) circuit to ground.

Is the resistance above 5.0 ohms?

Yes
Replace the Controller Anti-Brake in accordance with the service manual. Refer to the symptom *Replacing the Controller Anti-Lock Brake for additional information
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)

No
Repair the Fused B(+) circuit short to ground.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



5. FUSED B(+) CIRCUIT OPEN

--------------------------------------------------------------------------------
Remove the ABS PUMP Fuse.
Disconnect the CAB harness connector.
Measure the resistance of the Fused B (+) circuit between the ABS PUMP Fuse Terminal and the CAB harness connector.

Is the resistance below 5.0 ohms?

Yes
Go To6

No
Repair the open in the Fused B(+) circuit.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



6. NO B+ SUPPLY TO FUSE

--------------------------------------------------------------------------------
Turn the ignition on.
Measure the voltage of the B(+) supply at the ABS PUMP Fuse terminal.

Is the voltage above 11 volts?

Yes
Go To7

No
Repair the B(+) Supply circuit.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



7. ABS PUMP MOTOR INOPERATIVE

--------------------------------------------------------------------------------
Turn the ignition off.
Disconnect the ABS Pump Motor connector.
Connect a 10 gauge jumper wire between ABS Pump Motor Fused B(+) circuit and a 40 Amp Fused B(+) circuit.
Connect a 10 gauge jumper wire between ABS Pump Motor ground circuit and ground.
Monitor ABS Pump Motor operation.

Is the ABS Pump Motor operating?

Yes
Go To8

No
Replace the ABS Pump Motor/Hydraulic Control Unit assembly.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



8. GROUND CIRCUIT OPEN

--------------------------------------------------------------------------------
Turn the ignition off.
Disconnect the CAB harness connector.
Measure the resistance of the CAB Ground circuits.

Is the resistance below 5.0 ohms?

Yes
Go To9

No
Repair the open in the Ground circuit.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



9. GROUND CIRCUIT HIGH RESISTANCE

--------------------------------------------------------------------------------
Make sure the ABS Pump Motor connector is secure.
Turn the ignition on.
With the scan tool, enable ABS Pump Motor actuation.

NOTE: NOTE: ABS Pump Motor will not operate, but voltage will be applied.


Measure the voltage drop across the ABS Ground circuit connection, with ABS Pump Motor actuation enabled.

Is the voltage below 0.1 volt?

Yes
Replace the Controller Anti-Lock Brake in accordance with the service manual.
Perform ABS VERIFICATION TEST - VER 1.(Refer to 5 - BRAKES/ELECTRICAL - DIAGNOSIS AND TESTING)

No
Repair the high resistance in the Ground circuit.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)



10. WIRING HARNESS INSPECTION

--------------------------------------------------------------------------------
Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
Make sure the Pump Motor connecter is secure.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes
Repair the Left Front Wheel Speed Sensor Signal circuit for a short to voltage.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE)

No
Test Complete.

BigIron70

May have gotten something into hcu causing pump to run. You could try flushing out brake system and hcu with clean brake fluid.

If replacing HCU and cab it will need to be programed.
ABS BRAKE BLEEDING
ABS system bleeding requires conventional bleeding methods plus use of a scan tool. The procedure involves performing a base brake bleeding, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second base brake bleeding procedure is then required to remove any air remaining in the system.

Perform base brake bleeding,(Refer to 5 - BRAKES - STANDARD PROCEDURE) OR (Refer to 5 - BRAKES - STANDARD PROCEDURE).
Connect scan tool to the Data Link Connector.
Select ANTILOCK BRAKES, followed by MISCELLANEOUS, then ABS BRAKES. Follow the instructions displayed. When scan tool displays TEST COMPLETE, disconnect scan tool and proceed.
Perform base brake bleeding a second time,(Refer to 5 - BRAKES - STANDARD PROCEDURE) OR (Refer to 5 - BRAKES - STANDARD PROCEDURE).
Top off master cylinder fluid level and verify proper brake operation before moving vehicle.

Bark

Yikes!! Nothing is easy anymore. All I want to do is change my pads like I have on other vehicles. Seems like it could go bad.

Onemoparnut

You are supposed to open the bleeders and let the fluid out there when you collapse the calipers on anything with abs.

Bark

Ok! Maybe I will still give it a try. Meanwhile, I hope BigBore050 will be able to work around it and keep us informed.

BigBore050

Thanks for all the help guys, Im going to try bleeding them after work, do you think I sould bleed them with the ABS box plugged in and humming or unpluged.

I am so kicking myself over this now that i heard the ABS pump may cost me $1000. I have probly done brakes 6 times now with ABS equiped and never opend the bleeder and never had a prob till now. but i guess it got me now shoulda took the 5 min to pull out the repair manual and do some reading so I knew what I was doing istead of thinking i knew

BigIron70

To properly bleed you will need a DRBIII
ABS BRAKE BLEEDING
ABS system bleeding requires conventional bleeding methods plus use of a scan tool. The procedure involves performing a base brake bleeding, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second base brake bleeding procedure is then required to remove any air remaining in the system.

Perform base brake bleeding,(Refer to 5 - BRAKES - STANDARD PROCEDURE) OR (Refer to 5 - BRAKES - STANDARD PROCEDURE).
Connect scan tool to the Data Link Connector.
Select ANTILOCK BRAKES, followed by MISCELLANEOUS, then ABS BRAKES. Follow the instructions displayed. When scan tool displays TEST COMPLETE, disconnect scan tool and proceed.
Perform base brake bleeding a second time,(Refer to 5 - BRAKES - STANDARD PROCEDURE) OR (Refer to 5 - BRAKES - STANDARD PROCEDURE).
Top off master cylinder fluid level and verify proper brake operation before moving vehicle.