P0073 INLET AIR TEMP SENSOR VOLTAGE TOO HIGH

When Monitored and Set Condition:

When Monitored: With 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

• DTC RETURNS
• INLET AIR TEMPERATURE SENSOR
• (K69) SIGNAL CIRCUIT OPEN
• (Y502) RETURN CIRCUIT OPEN
• (K69) SIGNAL CIRCUIT SHORTED
• INTERMITTENT CONDITION
• ECM

DIAGNOSTIC PROCEDURE

NOTE:Refer to VERIFICATION TESTS for appropriate verification test procedures.

1. Turn the ignition on. With the DRBIII®, erase DTCs. With the DRBIII®, read DTCs. With the DRBIII®, record all Freeze frame data. Did the DTC return?
   Yes --> Go To 2
   No --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
2. Turn the ignition off. Disconnect the Inlet Air Temp sensor harness connector. Check connectors - Clean/repair as necessary. Measure the resistance of the Inlet Air temp sensor Is the resistance between 300 and 90k ohms?
   Yes --> Go To 3
   No --> Replace the Inlet air temperature sensor. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
3. Disconnect the ECM harness connector. Check connectors - Clean/repair as necessary. Reconnect the Inlet Air Temp sensor harness connector. Measure the resistance between the (K69) inlet air temperature sensor signal circuit and (Y502) return circuit at the ECM connector. Is the resistance between 300 and 90k ohms?
   Yes --> Go To 6
   No --> Go To 4
4. Disconnect the inlet Air Temp sensor harness connector. Measure the resistance of the (K69) inlet air temperature sensor signal circuit between the sensor harness connector and the ECM harness connector. Is the resistance less than 10 Ohms?
   Yes --> Go To 5
   No --> Repair or replace the harness. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
5. Measure the resistance of the sensor (Y502) return circuit between the sensor harness connector and the ECM harness connector. Is the resistance less than 10 Ohms?
   Yes --> Go To 6
   No --> Repair or replace the harness. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
6. Check for a short circuit from the (K69) signal circuit to all other circuits at the ECM harness connector. Is the resistance more than 100 k ohms?
   Yes --> Go To 7
   No --> Repair or replace the harness for a short to ground in the signal circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
7. Reconnect the ECM harness connector. Turn the ignition on. With the DRBIII®, erase DTCs. While monitoring with DRBIII®, use a jumper wire and connect the sensor (K69) signal circuit to the sensor (Y502) return circuit at the sensor connector. Did the DTC P0072 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).