Cooling Fan Inoperative
Cooling Fan Inoperative (2.2L)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The engine cooling fan system consists of one cooling fan and two relays. The cooling fan has 2 windings in the motor, one winding is for low speed and the other winding is for high speed. The engine control module (ECM) grounds the low speed relay 1, and the high speed relay 2 control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.
Diagnostic Aids
* The KR20 engine cooling fan relays are identified as listed below:
- KR20C low speed COOL FAN 1 relay
- KR20D high speed COOL FAN 2 relay
* When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.
Reference Information
Schematic Reference
Engine Cooling Schematics (Diagrams)
Connector End View Reference
* Master Electrical Component List (A - Z Index)
* Component Connector End Views (Connector Views)
Description and Operation
Cooling Fan Description and Operation (Cooling Fan Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Electrical Center Identification Views (Application and ID)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, Observe the DTC information with a scan tool. DTC P0480 or P0481 should not be set.
• If a DTC is set, refer to DTC P0480 or P0481 (P0480).
2. Ignition ON, command each KR20 cooling fan relay ON and OFF with a scan tool. The G10 cooling fan should operate at a Low and High speed as commanded.
Circuit/System Testing
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Disconnect the harness connector at the G10 engine cooling fan.
2. Test for less than 1 ohm between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
Note: The following tests must be performed on each fan circuit.
3. Connect a test lamp between ground and the G10 fan circuit terminal listed below. Command the KR20 relay ON with a scan tool. The test lamp should illuminate:
* G10 Cooling Fan Low Speed Circuit Terminal 1
* G10 Cooling Fan High Speed Circuit Terminal 2
• If the test lamp does not illuminate, test the appropriate KR20 relay switch B+ circuit terminal 30 and the relay controlled output circuit terminal 87 for a short to ground, or for an open/high resistance. If the circuit tests normal, test or replace the appropriate KR20 cooling fan relay.
4. If all of the circuits and relays test normal, test or replace the G10 engine cooling fan.
Component Testing
KR20 Cooling Fan Relay
1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 70-110 ohm between terminals 85 and 86.
3. Measure the resistance between the terminals listed below. The DMM should display OL:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If less than the specified range, replace the KR20 cooling fan relay.
4. Connect a 20 A fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Test for less than 2 ohm between terminals 30 and 87.
• If greater than the specified range, replace the KR20 cooling fan relay.
G10 Engine Cooling Fan
1. Ignition OFF, disconnect the harness connector at the G10 engine cooling fan.
2. Connect a jumper wire between ground and the G10 ground circuit terminal 3.
3. Connect a 30 A fused jumper wire between B+ and the G10 B+ supply circuit terminals listed below. The cooling fan should operate at a Low and High speed:
* G10 Cooling Fan Low Speed Circuit Terminal 1
* G10 Cooling Fan High Speed Circuit Terminal 2
• If the cooling fan does not operate at both speeds, replace the G10 engine cooling fan.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Cooling Fan and Shroud Replacement (Service and Repair)