P0852 code definition
The code P0852 indicates that a malfunction was detected within the park/neutral switch input circuit. This code is only found in vehicles with both automatic transmissions and four-wheel-drive capability.
What the P0852 code means
The PCM uses data from the speed sensor, torque converter lock-up solenoid, the transfer case shift sensor, the transmission shift solenoids, and other sensors, to calculate engine RPM, engine timing, fuel delivery, and many other operations. If the data from these sensors indicate that the transmission shifter range is not falling within the set parameters, this code will be stored.
What causes the P0852 code?
In almost every instance, the P0852 code is linked to a transfer case range sensor that is not properly adjusted. However, there may be other causes, including:
- A defective range sensor.
- Any open, corroded, shorted, or damaged electrical components, including wiring and connectors.
- Improperly installed sensor retaining bolts.
- Corrosion within the sensor connector.
What are the symptoms of the P0852 code?
If the P0852 code is stored, the vehicle owner may observe several other symptoms, including:
- Failure to engage four-wheel drive.
- Very harsh shifting.
- Complete failure to shift.
- Reduced fuel efficiency.
- Illumination of the Check Engine light.
How does a mechanic diagnose the P0852 code?
To begin diagnosing the P0852 code, a mechanic must first verify the code with the OBD-II scanner. Then, they will visually inspect all the electrical components, and replace any faulty, open, shorted, or damaged elements. After this repair, and any others, they should clear the PCM and retest the system. This step ensures that the mechanic knows precisely which repair fixed the issue, and does not continue working on a vehicle that has been properly repaired. If the code returns after this step, the mechanic will move on to testing other components of the park/neutral switch until the issue has been discovered.
Common mistakes when diagnosing the P0852 code
Often, after a vehicle has undergone recent transmission repairs, the range sensor will be left improperly adjusted, and only needs a simple tweak to solve the issue. Many technicians report that parts are mistakenly blamed and replaced when this small readjustment was all that was necessary.
How serious is the P0852 code?
The P0852 code directly relates to the safe and proper operation of the vehicle; therefore, it is very important that this issue be repaired immediately. Failure to address this issue when it arises could lead to dangerous driving conditions, or a vehicle that will not operate at all.
What repairs can fix the P0852 code?
There are a few ways that a technician can address a P0852 code detection. They include:
- Readjustment of an improperly adjusted transfer case range sensor.
- Replacement of a defective range sensor.
- Repairing any open, corroded, shorted, or damaged electrical components, including wiring and connectors.
- Reinstalling an improperly installed sensor retaining bolts.
- Replacement of a corroded sensor connector.
Need help with a P0852 code?
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