P0480-COOLING FAN 1 CONTROL CIRCUIT

For a complete wiring diagram Refer to Section 8W.

When Monitored:
With the ignition on. Battery voltage greater than 10 volts.
Set Condition:
An open or shorted circuit is detected in the radiator fan relay control circuit for more than 2.7 seconds. One Trip Fault. Three good trips to turn off the MIL.

Possible Causes

INTERNAL (A16) FUSED B+ CIRCUIT

INTERNAL (F1) FUSED IGNITION SWITCH OUTPUT CIRCUIT

(N201) COOLING FAN NO.1 RELAY CONTROL CIRCUIT OPEN

(N201) COOLING FAN NO.1 RELAY CONTROL CIRCUIT SHORTED TO GROUND

LOW SPEED RADIATOR FAN RELAY

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1.LOW SPEED RADIATOR FAN RELAY OPERATION

Is the Cooling Fan Relay operating?

Yes

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 2

2.(A16) FUSED B+ CIRCUIT

Does the test light illuminate brightly?

Yes

Go To 3

Repair the open or short to ground in the (A16) Fused B+ circuit. Inspect the related fuse and repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3.(F1) FUSED IGNITION SWITCH OUTPUT CIRCUIT

Does the test light illuminate brightly?

Yes

Go To 4

Repair the open or short to ground in the (F1) Fused Ignition Output circuit. Inspect the related fuse and repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

4.LOW SPEED RADIATOR FAN RELAY RESISTANCE

Is the resistance between 60 to 80 ohms?

Yes

Go To 5

Replace the Low Speed Radiator Fan Relay.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5.(N201) COOLING FAN NO.1 CONTROL CIRCUIT OPEN

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis

Is the resistance below 5.0 ohms?

Yes

Go To 6

Repair the open in the (N201) Cooing Fan No.1 Relay Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

6.(N201) COOLING FAN NO.1 CONTROL CIRCUIT SHORTED TO GROUND

Is the resistance below 100 ohms?

Yes

Repair the short to ground in the (N201) Cooling Fan No.1 Relay Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 7

7.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Were there any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)