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Technical Description of OBD-II Trouble Code
The circuit for the Engine Oil Quality Sensor is registering a high reading.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to many OBD-II vehicles (1996-newer), including vehicles from General Motors, VW, Ford, BMW, Mercedes, etc. The exact repair steps may vary depending on the 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) indicating the overall status of the engine oil. This circuit monitors the quality, temperature, and level of the engine oil. The engine oil quality sensor is a key component within this circuit and is mounted to the engine oil pan. The exact location and function of the sensor vary depending on the vehicle, but the purpose of the circuit remains the same. Configurations may include instruments such as oil temperature, oil level, and/or oil pressure gauges or readouts to display the oil status on the dashboard and alert the driver.
When the ECM detects voltage or resistance that is significantly higher than the normal expected range within the oil quality sensor circuit, it sets code P252D and may illuminate the check engine light, service engine soon light, or both. In some cases, the ECM may shut down the engine and prevent it from restarting until the issue is resolved and the code is cleared.
An oil quality sensor:
What is the severity of this DTC?
This code is considered severe and requires immediate attention because insufficient lubrication or oil pressure can cause rapid and permanent damage to internal engine components.
What are some of the symptoms of the code?
Symptoms of a P252D trouble code may include:
What are some of the common causes of the code?
Possible causes for this P252D code may include:
What are some P252D troubleshooting steps?
The first step in troubleshooting any malfunction is to research the Technical Service Bulletins (TSBs) specific to the vehicle’s year, model, and power plant. This can save time by providing guidance in the right direction.
The second step is to check the condition of the engine oil and ensure it is at the appropriate level. Then, locate all components associated with the engine oil quality sensor circuit and inspect them for any obvious physical damage. Depending on the vehicle, this circuit may include several components such as the oil quality sensor, switches, fault indicators, an oil pressure gauge, and the ECM. Conduct a thorough visual inspection of the associated wiring for any visible defects such as scraping, rubbing, bare wires, or burn spots. Next, check the connectors and connections for security, corrosion, and damaged pins. This process should include all wiring connectors and connections to all components, including the ECM. Consult the vehicle’s specific technical data 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 are highly vehicle-specific and require advanced equipment for accurate execution. These procedures involve using a digital multimeter and referencing the specific technical data for the vehicle.
Voltage Checks
The reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. The troubleshooting charts and sequence provided in the specific technical data will assist in an accurate diagnosis.
If this process reveals the absence of a power source or ground, continuity testing may be necessary to check the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power removed from the circuit, and the normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity indicates faulty wiring that is open, shorted, or corroded and must be repaired or replaced.
What are some common repairs for this code?
Common Mistake
We always recommend seeking professional mechanical service to resolve this issue. However, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to be addressed. If you are interested in this option, please upload your ECU file to our portal.
