P252D Engine Oil Quality Sensor Circuit High
OBD-II Trouble Code Technical Description
Engine Oil Quality Sensor Circuit High
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from General Motors, VW, Ford, BMW, Mercedes, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
OBD-II trouble code P252D and related codes P252A, P252B, P252C, and P252E are associated with the engine oil quality sensor circuit.
The purpose of the oil quality sensor circuit is to send a signal to the Engine Control Module (ECM) representing the overall status of the engine oil. This circuit monitors the quality, temperature and the level of the engine oil. The engine oil quality sensor is one of the main components within this circuit and is mounted to the engine oil pan. The exact location and how the sensor functions is vehicle specific, but the purpose of this circuit is the same. Configurations will vary based on the instruments incorporated to monitor the engine oil and display the status on the dashboard to alert the driver. Some vehicles may be equipped with oil temperature, oil level and/or oil pressure gauges or readouts.
When the ECM detects voltage or resistance that is too high above the normal expected value range within the oil quality sensor circuit, code P252D will be set and the check engine light, service engine soon light or both may be illuminated. In some situations, the ECM may shut the engine down and prevent it from restarting until the issue is corrected and the code has been cleared.
An oil quality sensor:
What is the severity of this DTC?
The severity of this code is severe and requires immediate attention because insufficient lubrication or oil pressure can cause permanent damage to internal engine components very rapidly.
What are some of the symptoms of the code?
Symptoms of a P252D trouble code may include:
Engine may not crank over Low oil pressure gauge reading Service engine soon light illuminated Check engine light illuminated Check Oil message on instrument clusterWhat are some of the common causes of the code?
Causes for this P252D code may include:
Defective engine oil quality sensor Low engine oil level Poor quality oil Faulty or damaged wiring Corroded, damaged or loose connector Defective ECMWhat are some P252D troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB's) for the specific vehicle by year, model and power plant. In some circumstances, this can save a lot of time in the long run by pointing you in the right direction.
The second step is to check the condition of the engine oil and confirm it is serviced to the appropriate level. Then locate all components associated with the engine oil quality sensor circuit and look for obvious physical damage. Based on the specific vehicle, this circuit may incorporate several components including the oil quality sensor, switches, fault indicators, an oil pressure gauge and the ECM. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burn spots. Next is to check the connectors and connections for security, corrosion and damaged pins. This process must include all wiring connectors and connections to all components including the ECM. Consult the specific tech data for the vehicle to verify the configuration of the oil quality sensor circuit and confirm every component incorporated within the circuit which may include a fuse or a fuse-able link.
Advanced Steps
The advanced steps become very vehicle specific and require the appropriate advanced
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