Error Code P052E is defined as Positive Crankcase Ventilation Regulator Valve Performance. This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, especially those made since 1996 up to present. It is particularly common, but not limited to vehicles from Dodge, Ford, Ram, Volvo, etc. Specifications on the definition, troubleshooting, and repairs, of course, may vary from one make to another.

When Error Code P052E is registered in your vehicle’s memory system, that means the PCM (powertrain control module, also known as the ECM or engine control module in other vehicle makes) has detected a signal coming from the CKP (crankcase pressure sensor) that is inappropriate for the existing degree of pressure.

The PCM monitors the pressure (air density) in the engine and measures it via an input voltage from the CKP sensor. Unit of pressure is measured in either kilopascal (kPa) units or inches of mercury (Hg). The CKP sensor is typically found in or near one of the valve covers.

To prevent oil leaks, the lower end of the internal combustion engine is sealed, creating a certain amount of pressure. This change of pressure is caused by a sudden change of temperature, as the engine oil creates vapor, along with the rapid centrifugal motion of the connecting rods, crankshaft, etc.

The PCV (positive crankcase ventilation) system draws pressure from the crankcase by using a carefully controlled intake vacuum, through a specially designed PCV valve. This valve only allows single direction of flow. In most applications, the PCV valve uses a straight vacuum from the intake manifold. Many PCV vacuums are regulated via electronically controlled PCV regulator valve. To determine how much vacuum pressure is needed for the PCV for optimum performance, the PCM uses input signal from the CKP sensor. To complete the circuit, there must be a constant supply of battery voltage to one of the terminals of the PCV regulator valve, while the PCM simultaneously supplies ground as needed, position the regulator valve in its housing, and realize the desired degree of PCV vacuum.

If the PCM determines that the desired crankcase pressure cannot be achieved with the PCV regulator valve, then the Error Code P052E will be stored.

Common Symptoms

As with other error codes, this code activates the Check Engine light and registers the code to the vehicle’s memory system. Other common symptoms include:

  • Oil leaks
  • Hissing (sucking) noise coming from the engine area
  • Smoke (steam) coming from the underhood
  • Other drivability problems caused by vacuum leaks

Possible Causes

Common causes of this code include:

  • Damaged PCV regulator valve
  • Faulty PCV valve
  • Faulty crankcase pressure sensor
  • Open or shorted PCV regulator valve or CKP sensor wiring
  • Damaged or programming error in the PCM

How to Check

To diagnose this code properly, you will need manual vacuum pressure gauge, a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.

Next, prior to diagnosing the CKP and PCV related codes, perform a manual vacuum pressure test. If there is not enough vacuum from the engine, then it must be repaired before moving on to the next step. A manual vacuum test is done by disconnecting the PCV vacuum hose and attaching the vacuum pressure gauge to it. The vehicle information will have the specification regarding the minimum engine vacuum.

Next, check all PCV hoses, look for signs of cracking or breakage and make repairs as necessary. Cracked or collapsed PCV vacuum hoses can lead to P052E, and similar codes.

If the engine is in good shape, and without vacuum leaks, continue inspecting the PCV regulator valve and CKP sensor connectors and wirings. Repair as needed.

Next, scan the vehicle’s diagnostic port and get all the codes stored, as well as their freeze frame data. Write this information down. Then, clear the codes and test-drive the vehicle.

Get the connector face views, connector pin-out charts, wiring diagrams, component testing procedures, and specifications from the vehicle information source. You will need this information for further diagnosis.

Professional technicians will check a lot of components to thoroughly diagnose this code, which includes:

  • Testing the PCV regulator valve and circuits at KOEO (key on, engine off)
  • Testing the PCV regulator valve voltage output circuit at the PCM connector
  • Testing the CKP sensor during DVOM
  • Use DVOM to test reference voltage (typically -5V) and ground at the CKP sensor connector
  • Testing the CKP sensor signal circuit voltage using the DVOM
  • Testing the CKP sensor signal circuit at the PCM connector

How to Fix

Depending on the diagnosis, repairs for the code include:

  • Replacement of the PCV regulator valve
  • Repair or replacement of open or short circuit between the PCV regulator valve and PCM connector
  • Replacement of the CKP sensor
  • Replacement or reprogramming of the PCM
  • Repair or replacement of open or short circuit between the CKP sensor signal circuit and PCM connector


Incorrect crankcase pressure can lead to engine oil leaks, which can cause further damage to the engine since it will be not enough oil to work efficiently. Thus, code P052E should be categorized as severe and must be addressed as soon as possible.