P0480-FAN 1 CONTROL CIRCUIT OPEN CIRCUIT
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition on and the ECM Low Speed Rad Fan Relay command off.
- Set Condition:
The ECM does not detect voltage on the Low Speed Rad Fan Relay Control circuit.
| Possible Causes |
| INTERMITTENT CONDITION |
| ASD RELAY OUTPUT CIRCUIT OPEN |
| LOW SPEED RADIATOR FAN RELAY |
| (N201) LOW SPEED RADIATOR FAN CONTROL CIRCUIT SHORTED TO GROUND |
| (N201) LOW SPEED RADIATOR FAN CONTROL CIRCUIT OPEN |
| ENGINE CONTROL MODULE |
Diagnostic Test
1. CHECK FOR ACTIVE DTCNOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the scan tool, actuate the Low Speed Radiator Fan Relay.
Does the Radiator Fan cycle on and off?
Yes
- Go To 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. ASD RELAY OUTPUT CIRCUIT OPEN
Turn the ignition off.
Remove the Low Speed Radiator Fan Relay from the PDC.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the ASD Relay Output circuit.
Did the test light illuminate brightly?
Yes
- Go To 3
No
- Repair the ASD Relay Output circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
3. LOW SPEED RADIATOR FAN RELAY
Turn the ignition off.
Install a known good relay in place of the Low Speed Radiator Fan Relay.
Turn the ignition on.
With the scan tool, actuate the Low Speed Rad Fan Relay.
Does the Radiator Fan cycle on and off?
Yes
- Replace the Low Speed Radiator Fan Relay.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Go To 4
4. (N201) LOW SPEED RADIATOR FAN CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Remove the Low Speed Radiator Fan Relay from the PDC.
Disconnect the ECM C1 harness connectors.
Measure the resistance between ground and the (N201) Low Speed Radiator Fan Control circuit at the PDC.
Is the resistance above 1000 ohms?
Yes
- Go To 5
No
- Repair the (N201) Low Speed Radiator Fan Control circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
5. (N201) LOW SPEED RADIATOR FAN CONTROL CIRCUIT OPEN
Measure the resistance of the (N201) Low Speed Radiator Fan Control circuit between the PDC and the ECM C1 harness connector.
Is the resistance below 10.0 ohms?
Yes
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Repair the Low Speed Radiator Fan Control circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).