Diagnostic Test

CHECK FOR RELATED DTCS
1. Turn the ignition on.
2. With the scan tool, read Electric Vehicle Control Unit (EVCU) DTCs.
  Are there any System Voltage, or Sensor Reference Voltage DTCs present?
  
  Yes
  - Refer to the DTC INDEX - 500E and perform the appropriate diagnostic procedure.
  No
  - Go To 2
CHECK IF THE DTC IS ACTIVE
1. With the scan tool, read Electric Vehicle Control Unit (EVCU) DTCs.
  Is the status for this DTC Active?
  
  Yes
  - Go To 3
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
CHECK THE (F852) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the A/C Pressure Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (F852) 5-Volt Supply 1 circuit at the A/C Pressure Sensor harness connector.
  Is the voltage above 4.8 volts?
  
  Yes
  - Go To 4
  No
  - Repair the (F852) 5-Volt Supply 1 circuit for an open or high resistance.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND
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 harness connector.
3. Measure the resistance between ground and the (C18) A/C Pressure Signal circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100K Ohms?
  
  Yes
  - Repair the (C18) A/C Pressure Signal circuit for a short to ground.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 5
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR A SHORT TO THE (C918) A/C PRESSURE GROUND CIRCUIT
1. Measure the resistance between the (C18) A/C Pressure Signal circuit and the (C918) A/C Pressure Ground circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100K Ohms?
  
  Yes
  - Repair the (C18) A/C Pressure Signal circuit for a short to the (C918) A/C Pressure Ground circuit.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 6
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (C18) A/C Pressure Signal circuit between the A/C Pressure Transducer harness connector and the EVCU C2 harness connector.
  Is the resistance below 1.0 Ohm?
  
  Yes
  - Go To 7
  No
  - Repair the (C18) A/C Pressure Signal circuit for an open or high resistance.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
AC PRESSURE TRANSDUCER
1. Turn the ignition off.
2. Reconnect the EVCU C2 harness connector.
3. Connect a jumper between the (F852) 5-Volt Supply circuit and the (C18) A/C Pressure Signal circuit at the A/C Pressure Transducer harness connector.
4. Turn the ignition on.
5. With the scan tool, read the AC Pressure Sensor Signal voltage.
  Is the voltage above 4.8 volts?
  
  Yes
  - Replace the A/C Pressure Transducer in accordance with the Service Information. Refer to TRANSDUCER, A/C PRESSURE, REMOVAL .
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 8
ELECTRIC VEHICLE CONTROL UNIT (EVCU)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Electric Vehicle Control Module (EVCU).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  
  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 and repair as necessary. If a new controller is installed and short to voltage is present, it will damage the new controller.
  - Replace and program the Electric Vehicle Control Module (EVCU) in accordance with the Service Information. Refer to UNIT, ELECTRIC VEHICLE CONTROL (EVCU), REMOVAL .
  - Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .