P0936 code definition
The P0936 trouble code notes an intermittent circuit error in the hydraulic pressure sensor.
What the P0936 code means
The P0936 code is a generic OBD-II trouble code that detects a problem with the hydraulic pressure sensor circuit. The purpose of the hydraulic pressure system is to provide power to help the automatic transmission shift gears. Each gear has a hydraulic circuit associated with it, and when the vehicle calls for an upshift or a downshift, the different hydraulic circuits will engage or disengage to make the shift happen. This is all controlled by the powertrain control module (PCM) and transmission control module (TCM), which calculate the proper shift strategy by accounting for various different engine factors and conditions. The PCM then monitors the hydraulic pressure by receiving data from the hydraulic pressure sensors. If the PCM receives an abnormal signal, or no signal at all from the hydraulic pressure sensors, then the P0936 trouble code may be stored.
What causes the P0936 code?
The P0936 trouble code is almost always the result of damaged electrical components. This can include blown fuses, corroded cables, short or open wires, or a loss of ground. Other potential causes of the code are a defective hydraulic pressure sensor, and a faulty PCM or TCM.
What are the symptoms of the P0936 code?
When the P0936 trouble code is detected, the check engine soon warning light will likely illuminate on the vehicle’s instrument panel. Transmission problems are usually evident, such as the failure to shift into certain gears (which can result in slow acceleration or excessive engine speed), and harsh shifting. Most vehicles will also experience reduced fuel efficiency.
How does a mechanic diagnose the P0936 code?
The P0936 code will be diagnosed with a standard OBD-II trouble code scanner. A trained technician will use the scanner to view the freeze frame data and assess the P0936 code. The scanner will also be used to check for the presence of any other trouble codes, as codes should always be addressed in the order in which they appear. The codes will then need to be reset, and the vehicle restarted, so the mechanic can see if the P0936 code returns. If it does not, then an erroneous trigger or an intermittent error are likely to blame.
If the code does return, then the mechanic will begin by visually inspecting the electrical components in the hydraulic pressure sensor system, and replacing any that are damaged. Next, the ground voltage should be checked, and then the mechanic can perform an inspection on the hydraulic pressure sensor. If no issue is found, a thorough inspection of the PCM and TCM will be required.
When any component is repaired or replaced, the mechanic will need to reset the codes, restart the vehicle, and again check to see if the P0936 code remains detected. By doing this, the technician will know when the issue is resolved.
Common mistakes when diagnosing the P0936 code?
The most commonly made mistake when diagnosing this code comes from not properly following the OBD-II diagnosis protocol. The protocol should always be followed exactly, to ensure that diagnoses and repairs are thorough and efficient.
It is fairly common for hydraulic pressure sensors to be replaced erroneously, when an electrical component was the only problem in the system.
How serious is the P0936 code?
In most cases, a vehicle with a P0936 code can still be driven, though there may be drivability issues. If the code is not addressed, severe damage can be done to the transmission, so an inspection should be scheduled as soon as the code is detected.
What repairs can fix the P0936 code?
Repairs for the P0936 trouble code are:
- Replacement of the electrical components in the system
- Replacement of the hydraulic pressure sensor
- In rare cases, replacement of the PCM or TCM
Additional comments for consideration regarding the P0936 code
It is very uncommon for the P0936 code to be the result of a defective PCM or TCM, so all other options should be checked before control module failure is assumed. If the PCM or TCM does need to be replaced, then a reprogramming will be required.
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