How severe is 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 quickly.
What are some of the symptoms of the code?
Symptoms of a P252B fault code may include:
- Engine cannot start
- Oil pressure gauge reading
- Service engine soon light
- Check engine light on
- Check oil message on the instrument cluster
What are some common causes of the code?
Causes
of this P252B code may include:
- Faulty engine oil quality sensor
- Low engine oil level
- Poor quality oil
- Faulty or damaged wiring
- Corroded, damaged, or loose connector
- Faulty ECM
What are the troubleshooting steps for P252B?
The first step in the troubleshooting process for any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you a lot of time in the long run by pointing you in the right direction.
The second step is to check the engine oil condition and confirm it is maintained at 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 that the associated wiring does not have obvious defects such as scraping, rubbing, bare wires, or burns. Then 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 vehicle-specific technical data to verify the oil quality sensor circuit configuration and confirm each component incorporated into the circuit that may include a fuse or fusible link.
Advanced Steps
Advanced steps become very vehicle-specific and require appropriate advanced equipment to operate accurately. These procedures require a digital multimeter and vehicle-specific technical references.
Voltage Checks
Reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the appropriate sequence to follow to help you make an accurate diagnosis.
If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open, shorted, or corroded and must be repaired or replaced.
What are the common repairs for this code?
- Replacing the engine oil quality sensor
- Cleaning corrosion from connectors
- Repairing or replacing faulty wiring
- Changing oil and filter
- Repairing or replacing faulty ground straps
- ECM replacement
Common Mistake
- Replacing the engine oil quality sensor when faulty wiring is causing the ECM to set this code.
- I hope the information in this article has been helpful in pointing you in the right direction to fix the issue with your oil quality sensor circuit error code. This article is strictly informational, and your vehicle-specific technical data and service bulletins should always take priority.