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P0873 is a diagnostic trouble code (DTC) for "Transmission Fluid Pressure Sensor/Switch C Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $154.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $50.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
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The P0873 trouble code refers to a detected anomaly in the transmission fluid pressure. The reported pressure has fallen beyond the manufacturer's set parameters.
The vehicle's Powertrain Control Module (PCM) is fed information on many aspects of the vehicle's systems, including transmission fluid pressure. In a P0873, the sensor in the transmission system's C circuit has detected a pressure level that extends beyond the manufacturer's set limits.
A P0873 is most often caused by a problematic transmission system.
In very rare cases, the PCM itself may be faulty and reporting false information. Because PCMs are notoriously difficult to repair or reprogram, this slight possibility should only be considered if all other possible causes have been exhausted completely.
A P0873 scenario typically involves problems with the transmission. When the vehicle is being used, there will usually be a distinct smell of burnt transmission fluid, as well as smoke possibly emanating from the transmission system. Practical concerns regarding the transmission system, including gear slippage, are also possible. For the sake of identifying and diagnosing the issue, the P0873 code and dashboard trouble lamp will be activated to alert the operator.
The P0873 trouble code may be first diagnosed by uplinking to the vehicle's onboard computer with an OBD-II code reader. The components related to the transmission system (including the sensor that picked up the issue) should be thoroughly inspected for signs of wear. If a leak has been detected at some part of the transmission system's body, a visual mark of it should be made for reference during the repair stage.
Technicians have reported the P0873 code cause to be underestimated and mistakenly blamed on bad transmission fluid. Instead, the primary cause (a faulty transmission pump, for instance) may have subsequently resulted in fluid issues.
A P0873 trouble code suggests there are serious issues with the transmission system. Because of this, it is not recommended using the car until the transmission system has been checked thoroughly and addressed accordingly.
If any components in the transmission system (including the sensor itself) have been identified as faulty, they should be repaired or replaced outright
Leaky segments in the transmission system should be patched up and repaired
Any corroded, broken or faulty wiring related to the transmission system, including connectors, should be repaired accordingly
Following your set of repairs, the vehicle should be test-driven immediately. Giving the vehicle a few minutes of use will allow you to see whether or not the code has been solved
In the rare instance that the PCM itself may be faulty, it will need to be repaired and reprogrammed, or replaced outright
Due to the expensive and long time it takes to commit to PCM repairs, this option should only be pursued if it's made absolutely clear that the PCM is at fault.
The particular pressure limits needed to trigger a P0873 code will vary depending on the model and manufacturer of the vehicle.
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