Initial Inspection and Diagnostic Overview

Engine Cooling
1. Verify the customer concern.
2. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
3. Visually inspect for obvious signs of mechanical or electrical damage.
4. If the concern is not an electrical fault and is not visually evident, verify the concern and refer to the symptom chart.
5. If the concern is an electrical fault and is not visually evident, use a fault code reader to retrieve the fault codes before proceeding to the symptom chart.

Visual Inspection Chart

Visual Inspection Chart:

DTC P0480; High/low signal from the cooling fan motor control module to the engine control module (ECM)

Possible Source(s):
- Fuse 8 (80A), engine compartment fuse box.
- Circuit.
- Cooling fan motor.
- Cooling fan motor control module.
- ECM.

Action(s) to take:
^ GO to Pinpoint Test A. Pinpoint Test G92380p1: DTC P0480; High/Low Signal From the Cooling Fan Motor Control Module to the ECM

Loss of coolant

Possible Source(s):
- Hoses.
- Hose connections.
- Radiator.
- Water pump.
- Heater core.
- Gaskets.
- Coolant expansion tank.
- Coolant pressure cap.
- Engine casting cracks.
- Engine core plugs.

Action(s) to take:
^ Go to Pinpoint Test B. Pinpoint Test G92380p2: Loss of Coolant G92380t13: Visual Inspection

Engine overheats

Possible Source(s):
- Engine coolant.
- Thermostat.
- Fuse 8 (80A), engine compartment fuse box.
- Circuit.
- Cooling fan motor(s).
- Radiator.
- Water pump.
- Water pump drive belt.
- Engine coolant temperature (ECT) sensor.
- ECM.
- Cooling fan motor control module.

Action(s) to take:
^ Go to Pinpoint Test C. Pinpoint Test G92380p3: the Engine Overheats G92380t14: Check Coolant

Engine block heater does not operate properly

Possible Source(s):
- Block heater power cable.
- Block heater.

Action(s) to take:
^ Go to Pinpoint Test D. Pinpoint Test G92380p4: the Engine Block Heater Does Not Operate

The engine does not reach normal operating temperature

Possible Source(s):
- Thermostat.

Action(s) to take:
^ INSTALL a new thermostat.