Pinpoint Test H - Abs Control Pump Motor Diagnosis

Check ABS Pump Motor (With Ignition Off)

Turn ignition off. With vehicle in a quiet area, listen to ABS pump motor. If pump motor does not run continuously, go to step 3). If pump motor runs continuously, replace ABS relay and go to next step.

Check ABS Pump Motor (Engine Running)

Start engine. Again, listen to ABS pump motor. If pump motor runs continuously, replace Hydraulic Control Unit (HCU). If pump motor does not run continuously, repair made in step 1) has corrected problem. Clear codes and retest system.

Check ABS Operation

Drive vehicle a minimum of 6 MPH, and observe ABS warning light. If ABS light is off, repair made in step 2) has corrected problem. If ABS warning light is on, go to next step.

Check Fuse

Remove and inspect fuse No. 3 (60-amp) from engine compartment fuse block. If fuse is blown, go to next step. If fuse is okay, go to step 6).

Check For Short To Ground

Disconnect Hydraulic Control Unit (HCU) 8-pin connector. Measure resistance between ground and output side of fuse No. 3 cavity (Red/Yellow wire). If resistance is 10,000 ohms or more, install fuse and go to next step. If resistance is less than 10,000 ohms, repair short to ground in Red/Yellow wire.

Check For Open Circuit

Measure resistance between output side of fuse No. 3 cavity (Red/Yellow wire) and test pin No. 30 at breakout box. If resistance is 5 ohms or less, replace ABS relay. Clear codes and go to next step. If resistance is more than 5 ohms, repair open Red/Yellow wire. Clear codes and go to next step.

Check ABS Control Module

Drive vehicle a minimum of 6 MPH, and observe ABS warning light. If ABS light is off, repair made in step 6) has corrected problem. If ABS warning light is on, replace HCU.