P1508

P1508-CRANKCASE FILTER RESTRICTION - REPLACE FILTER

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The crankcase pressure sensor is used to monitor the pressure inside the crankcase. The ECM supplies the crankcase pressure sensor a 5-volt reference voltage. When the crankcase pressure is low, the sensor signal voltage is low. When the crankcase pressure is high, the sensor signal voltage is near the 5-volt reference voltage. The ECM monitors the crankcase pressure signal circuit voltage to calculate the pressure of the air within the crankcase. The ECM does not illuminate the MIL or ETC lamp for any of the crankcase pressure faults.

- When Monitored:
Engine speed greater than 500 rpm.

- Set Condition:
The ECM detects the crankcase pressure exceeds a calibratable limit.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. P1508 ACTIVE
Ignition on, engine not running.
With the scan tool, read DTC's.
Is fault code P1508 active?

Yes


- Replace the crankcase breather filter and check for progressive engine damage due to high crankcase pressures.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


No


- Clear DTC, repair complete.