Diagnostic Test

CHECK IF DTC IS CURRENT
1. Using the scan tool, read EVCU DTCs.
2. Record the Environmental Data and any DTCs.
3. Clear DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. Read EVCU DTCs.
  Did the DTC reset?
  
  Yes
  - Go To 2
  No
  - Go to 5
CHECK THE (N27) RADIATOR COOLING FAN FEEDBACK CIRCUIT OPEN/HIGH RESISTANCE
1. Turn the ignition off. Remove the key from the Ignition Switch, close doors and allow the EVCU to shut down.
  NOTE:
  Allow up to two minutes for the EVCU to shut down. Opening the vehicle door will interrupt the shut down process.
2. Disconnect the EVCU C1 and C2 harness connectors.
3. Disconnect the Radiator Cooling Fan Module harness connector.
4. Measure the resistance of the (N27) Radiator Cooling Fan Feedback circuit between the Radiator Cooling Fan Module harness connector and both EVCU C1 and C2 harness connectors.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the open/high resistance in the (N27) Radiator Cooling Fan Feedback circuit.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (N27) RADIATOR COOLING FAN FEEDBACK CIRCUIT SHORTED TO GROUND
1. Measure the resistance of the (N27) Radiator Cooling Fan Feedback circuit between ground and both EVCU C1 and C2 harness connectors.
  Is the resistance above 100k Ohms?
  
  Yes
  - Go To 4.
  No
  - Repair the (N27) Radiator Cooling Fan Feedback circuit for a short to ground.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (H99) RADIATOR COOLING FAN FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE
NOTE:
A short to voltage could possibly damage the controller causing this DTC to set. Before replacing the EVCU, check the circuit(s) for a short to voltage. If a new controller is installed and short to voltage is present, it will damage the new controller.

Ignition off.
1. Reconnect the EVCU harness connectors.
2. Ignition on.
3. Check the (H382) Radiator Cooling Fan Feedback circuit for a short to voltage.
  Was a shot to voltage found?
  
  Yes
  - Repair the short to voltage (H382) Radiator Cooling Fan Feedback circuit.
  - Reconnect all disconnected components, clear DTCs and retest for DTC.
  - If DTC resets, replace and program the EVCU. Refer to UNIT, ELECTRIC VEHICLE CONTROL (EVCU), REMOVAL .
  No
  - Using the schematics as a guide, check the Electric Vehicle Control Unit (EVCU) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the EVCU. Refer to UNIT, ELECTRIC VEHICLE CONTROL (EVCU), REMOVAL .
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
PERFORM RADIATOR ACTUATOR TEST
1. With the scan tool, perform the EVCU Radiator Fan Actuator Procedure while listening for the fans to operate.
  Do both fans operate?
  
  Yes
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
  No
  - Replace the Radiator Fan Module. Refer to FAN, COOLING, REMOVAL .
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .