P1646

P1646-HYDRAULIC COOLING FAN CONTROL CIRCUIT LOW

For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Ignition on and engine running.

- Set Condition:
An open or shorted condition in the Hydraulic Fan Solenoid Control circuit is detected by the Front Control Module.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding Initial Inspection and Diagnostic Overview.

Diagnostic Test

1. HYDRAULIC COOLING FAN OPERATION
Ignition on, engine not running.
Using the scan tool, perform the Hydraulic Fan Solenoid Test.
Does the Hydraulic Cooling Fan operate properly?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition.

No

- Go To 2

2. (A916) FUSED B+ CIRCUIT CHECK

Turn the ignition off.
Disconnect the Hydraulic Cooling Fan Module harness connector.
Using a 12-volt test light connected to ground, probe the (A916) Fused B+ circuit in the Hydraulic Cooling Fan Module harness connector.
Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short to ground in the (A916) Fused B+ circuit
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. (K173) HYDRAULIC RADIATOR FAN SOLENOID CONTROL CIRCUIT OPEN BETWEEN THE FAN AND IPM C2 HARNESS CONNECTOR

Disconnect the IPM C2 40 way connector.
Measure the resistance of the (K173) Hydraulic Radiator Fan Solenoid control circuit from Fan Module harness connector to the IPM C2 40 way harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go To 4

No

- Repair the excessive resistance in the (K173) Hydraulic Radiator Fan Solenoid Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. (K173) HYDRAULIC RADIATOR FAN SOLENOID CONTROL CIRCUIT SHORTED TO GROUND BETWEEN THE FAN AND IPM C2 HARNESS CONNECTOR

Connect the IPM C2 40 way connector.
Disconnect the IPM FCM 49 way harness connector.
Measure the resistance of the (K173) Hydraulic Radiator Fan Solenoid control circuit from Fan Module harness connector to the IPM FCM 49 way harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the excessive resistance in the (K173) Hydraulic Radiator Fan Solenoid Control circuit in the IPM.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. (K173) HYDRAULIC RADIATOR FAN SOLENOID CONTROL CIRCUIT SHORTED TO GROUND BETWEEN THE FAN AND IPM FCM 49 WAY HARNESS CONNECTOR

Measure the resistance between ground and the (K173) Hydraulic Radiator Fan Solenoid Control circuit in the Fan Module harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (K173) Hydraulic Radiator Fan Solenoid Control circuit in the IPM.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. FRONT CONTROL MODULE (FCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Hydraulic Cooling Fan and the Front Control Module (FCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Hydraulic Cooling Fan and the Front Control Module (FCM) connectors.
Search for any Technical Service Bulletins that may apply.
Were there any problems found?

Yes

- Repair as necessary.
- Perform BODY VERIFICATION TEST. Body Verification Test.

No

- Replace and program the Front Control Module.
- Perform BODY VERIFICATION TEST. Body Verification Test.