Circuit/System Testing
WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground in the circuit.
- If infinite resistance, replace the G10 Cooling Fan Motor.
- Go to next step: If the test lamp illuminates
- Connect a DMM, set on the diode setting, between the G10 Cooling Fan Motor control circuit terminal 4 and ground.
- Verify the DMM reading is greater than 2.5 V or displays O.L. with the cooling fan commanded OFF.
- If 2.5 V or less
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
- Disconnect the harness connector X1 at the K20 Engine Control Module.
- Test for infinite resistance between the G10 Cooling Fan Motor control circuit terminal 4 and ground.
- If less than infinite resistance, repair the short to ground in the circuit.
- If infinite resistance, replace the K20 Engine Control Module.
- Go to next step: If greater than 2.5 V or displays O.L.
- Command the cooling fan ON to 90% with a scan tool.
- Verify the DMM reading is less than 1 V.
- If 1 V or greater
- Ignition OFF.
- Disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON.
- Test for less than 1 V between the G10 Cooling Fan Motor control circuit terminal 4 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V.
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 2 Ω in the circuit end to end.
- If 2 Ω or greater, repair the open in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: If less than 1 V
- Replace the K20 Cooling Fan Control Module.
NOTE:
The cooling fan speed output circuit is pulled-up to a voltage within the ECM, 2-3 volts on the output circuit is normal.