P1506

P1506-CRANKCASE DEPRESSION REGULATOR VALVE PERFORMANCE

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 Crankcase Depression Valve is used to ensure the crankcase pressure does not go below a certain limit. It is a mechanical valve in the closed crankcase ventilation system. It is designed to maintain crankcase pressures above -7 inH2O. This diagnostic will not run if there are any other Crankcase Pressure Sensor errors. The ECM does not illuminate the MIL or ETC lamp for any of the crankcase pressure faults.

- When Monitored:
Engine running

- 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. DTC ACTIVE
Ignition on, engine not running.
With the scan tool, read DTC's.
Is fault code P1506 active?

Yes


- Replace the Breather Filter Cover (the Crankcase Depression Valve is a part of this cover and is not serviceable). Check the system for any progressive damage due to excessively low crankcase pressures
- Perform POWERTRAIN VERIFICATION TEST VER (DIESEL). Powertrain Verification Test


No


- Clear DTC, repair complete