P0533 A/C SENDING UNIT VOLTS TOO HIGH

When Monitored and Set Condition:

When Monitored: With the ignition on and battery voltage greater than 10.4 volts.
Set Condition: The circuit voltage to the ECM is above a calibrated threshold for a certain period of time.

POSSIBLE CAUSES

• OTHER DTC'S
• A/C PRESSURE SENSOR
• (C18) SIGNAL CIRCUIT SHORTED TO BATTERY POSITIVE
• (K72E) 5-VOLT SUPPLY CIRCUIT SHORTED TO BATTERY POSITIVE
• (K55) RETURN CIRCUIT OPEN FROM ECM HARNESS CONNECTOR TO A/C HARNESS
• CONNECTOR
• ECM
• INTERMITTENT CONDITION

DIAGNOSTIC PROCEDURE

1. Turn the ignition on. With the DRBIII®, read DTCs. Are other DTCs present?
   Yes --> Repair other DTCs first. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 2
2. Disconnect the A/C pressure sending unit harness connector. Check connectors - Clean/repair as necessary. Measure the voltage between the (K72E) 5-volt supply circuit and (K55) return circuit of the sensor harness connector. Is the voltage between 4.5 and 5.5 volts?
   Yes --> Go To 3
   No --> Go To 4
3. While monitoring DRBIII®, use a jumper wire to connect the (K55) return circuit to the (C18) signal circuit at the sensor harness connector. Did P0532 set?
   Yes --> Replace the A/C pressure sensor. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 4
4. Turn the ignition off. Disconnect the ECM harness connectors. Check connectors - Clean/repair as necessary. Measure the voltage between the (K72E) 5-volt supply circuit at the harness connector and battery negative. Is the voltage less than 1 volt?
   Yes --> Go To 5
   No --> Repair the (K72E) 5-volt supply circuit shorted to the battery negative. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
5. Measure the voltage between the (C18) signal circuit at the harness connector and battery negative. Is the voltage less than 1 volt?
   Yes --> Go To 6
   No --> Repair the (C18) signal circuit shorted to the battery negative. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
6. Measure the resistance of the (K55) return circuit between the sensor harness connector and the ECM harness connector. Is the resistance less than 10 Ohms?
   Yes --> Go To 7
   No --> Repair the open (K55) return circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
7. Reconnect the ECM harness connectors. Turn the ignition on. While monitoring DRBIII®, use a jumper wire to connect the (K55) return circuit with the (C18) signal circuit at the sensor harness connector. Did DTC P0532 set?
   Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).