P0521 OIL PRESSURE SWITCH RATIONALITY

When Monitored and Set Condition:

When Monitored: While the key is on.
Set Condition: Oil pressure is detected with engine RPM = 0 for 30 seconds.

POSSIBLE CAUSES

• OIL PRESSURE SWITCH
• (G60) SIGNAL CIRCUIT OPEN
• INTERMITTENT CONDITION
• ECM

DIAGNOSTIC PROCEDURE

1. Turn the ignition off. Disconnect the Oil pressure switch harness connector. Check connectors - Clean/repair as necessary. Measure the resistance between the oil pressure switch terminal and ground. Is the resistance less than 10 ohms?
   Yes --> Go To 2
   No --> Replace the oil pressure switch. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
2. Disconnect the ECM harness connectors. Check connectors - Clean/repair as necessary. Measure the resistance of the oil pressure switch (G60) signal circuit between the oil pressure switch harness connector and the ECM harness connector. Is the resistance less than 10 ohms?
   Yes --> Go To 3
   No --> Repair the open Oil pressure (G60) signal circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
3. Reconnect the ECM harness connectors. Turn the ignition on. Measure the voltage between the oil pressure (G60) signal circuit at the oil pressure switch harness connector and ground. Is the voltage between 4.5 and 5.5 volts?
   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).