Auxiliary Coolant Pump Control Circuit Open (MTC)

B1080-AUXILIARY COOLANT PUMP CONTROL CIRCUIT OPEN (MTC)





For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

When Auxiliary Coolant Pump operation is requested.

- Set Condition:

If the (C43) Auxiliary Coolant Pump Driver circuit is open or shorted to voltage. This DTC has a maturing time of 10 seconds and a de-maturing time of 10 seconds. If the DTC's status changes from active to stored it will stay in memory for 100 ignition cycles.





NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test (MTC) for stored DTC test procedures. HVAC System Test (MTC)

Diagnostic Test

1.CHECK (C43) AUXILIARY COOLANT PUMP DRIVER CIRCUIT FOR A SHORT TO VOLTAGE





Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Turn the ignition on.

Measure the voltage of the (C43) Auxiliary Coolant Pump Driver circuit.

Is the voltage above 0.2 volts?

Yes

- Repair the (C43) Auxiliary Coolant Pump Driver circuit for a short to voltage.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 2

2.CHECK (C43) AUXILIARY COOLANT PUMP DRIVER CIRCUIT OPERATION





Turn the ignition off.

Reconnect the A/C Heater Control C1 harness connector.

Set the blend control to the full cold position.

Turn the ignition on.

With the scan tool, erase HVAC DTCs.

Turn the ignition off.

Disconnect the Auxiliary Coolant Pump harness connector.

Using a 12-volt test light connected to ground, back probe the (C43) Auxiliary Coolant Pump Driver circuit.

Turn the ignition on.

With the scan tool, select the following: Actuators, Auxiliary Coolant Pump, Start, and Constant On.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Go To 4

3.CHECK (Z931) GROUND CIRCUIT FOR AN OPEN





Turn the ignition off.

Measure the resistance of the (Z931) Ground circuit between ground and the Auxiliary Coolant Pump harness connector.

Is the resistance below 5.0 ohms?

Yes

- Replace the Auxiliary Coolant Pump.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Repair the (Z931) Ground circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4.CHECK (C43) AUXILIARY COOLANT PUMP DRIVER CIRCUIT FOR AN OPEN





Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Measure the resistance of the (C43) Auxiliary Coolant Pump Driver circuit between the A/C Heater Control C1 harness connector and the Auxiliary Coolant Pump harness connector.

Is the resistance below 5.0 ohms?

Yes

- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Repair the (C43) Auxiliary Coolant Pump Driver circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test