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Timing Control Pump Does Not Operate

  1. Disconnect auxiliary water pump relay (K22). Turn ignition on. Using a DVOM, measure voltage between ground and terminal No. 4 (Brown wire) of auxiliary water pump relay. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
  2. Repair open circuit or high resistance in Brown wire to auxiliary water pump relay. After repairing wire, reconnect wiring and components. Verify timing control pump operates properly.
  3. Measure resistance between ground and terminal No. 6 (Black wire) of auxiliary water pump relay harness connector. If resistance is less than 2 ohms, go to step 5). If resistance is not as specified, go to next step.
  4. Repair open circuit or high resistance in Black (ground) wire to auxiliary water pump relay. After repairing wire, reconnect wiring and components. Verify timing control pump operates properly.
  5. Locate test connector within the Engine Control Module (ECM) housing. Using a fused jumper wire, connect terminal No. 1 (Brown/Blue wire) of test connector to a known good ground. If engine cooling fan comes on at half speed, go to step 7). If engine cooling fan does not come on at half speed, go to next step.
  6. Perform ENGINE COOLING FAN DOES NOT OPERATE AT HALF SPEED  test.
  7. Measure voltage between ground and terminal No. 2 (Red/Blue wire) of auxiliary water pump relay (K22) wiring harness connector. If battery voltage is present, go to step 9). if battery voltage is not present, go to next step.
  8. Repair open circuit or high resistance in Red/Blue wire to auxiliary water pump relay. After repairing wire, reconnect wiring and components. Verify timing control pump operates properly.
  9. Remove fused jumper wire (at test connector). Install auxiliary water pump relay. Disconnect timing control pump. Connect fused jumper wire again. Measure voltage between ground and Brown/Green wire at timing control pump wiring harness connector. If battery voltage is present, go to step 11). If battery voltage is not present, go to next step.
  10. Check for open circuit or high resistance in Brown/Green wire between auxiliary water pump relay and timing control pump. If wire is okay, replace auxiliary water pump relay. After repairs, reconnect wiring and components. Verify timing control pump operates properly.
  11. Measure resistance between ground and Black (ground) wire terminal of timing control pump wiring harness connector. If resistance is less than 2 ohms, go to step 13). If resistance is not as specified, go to next step.
  12. Repair open circuit or high resistance in Black wire to timing control pump. After repairing wire, reconnect wiring and components. Verify timing control pump operates properly.
  13. Replace timing control pump. After replacing pump, reconnect wiring and components. Verify timing control pump operates properly.
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