Technical Description of OBD-II Trouble Code
The performance of Pressure Control Solenoid C or its failure to function properly
What does that signify?
This is a standard diagnostic trouble code (DTC) for transmissions and is typically applicable to OBD-II vehicles with automatic transmissions.
This may include vehicles from various manufacturers such as Ford, Mercury, Lincoln, Jaguar, Chevrolet, Toyota, Nissan, Allison/Duramax, Dodge, Jeep, Honda, Acura, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
When the P0796 OBD-II trouble code is triggered, it means that the Powertrain Control Module (PCM) has detected an issue with the Transmission Pressure Control Solenoid “C”. Most automatic transmissions have three solenoids, namely solenoid A, B, and C. The trouble codes associated with the “C” solenoid are codes P0795, P0796, P0797, P0798, and P0799. The specific code is determined by the particular malfunction that alerts the PCM and causes the Check Engine Light to illuminate.
The purpose of the Transmission Pressure Control Solenoids is to regulate the fluid pressure for the proper functioning of an automatic transmission. The PCM receives an electronic signal based on the pressure within the solenoids. An automatic transmission operates through bands and clutches that change gears by ensuring that fluid pressure is in the correct place at the right time. Based on signals from devices that monitor the vehicle’s speed, the PCM controls the pressure solenoids to direct fluid at the appropriate pressure to different hydraulic circuits, thereby changing the transmission gear ratio at the appropriate time.
The P0796 code is set by the PCM when the Pressure Control Solenoid “C” is not functioning correctly or is stuck in the “Off” position.
Example of a transmission pressure control solenoid:
What is the severity of this DTC?
Initially, the severity of this code is moderate, but if not addressed promptly, it can quickly escalate to a more severe level.
What are some of the symptoms of the code?
Symptoms of a P0796 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P0796 transmission code may include:
What are some P0796 troubleshooting steps?
Prior to starting the troubleshooting process for any malfunction, it is advisable to research the Technical Service Bulletins (TSB’s) specific to the vehicle’s year, model, and transmission. In some cases, this can save a significant amount of time by providing guidance in the right direction. It is also recommended to check the vehicle records to determine the last time the filter and fluid were changed, if possible.
Fluid & Wiring Inspections
The first step is to check the fluid level and examine the condition of the fluid for any contamination. Before changing the fluid, it is important to check the vehicle records to verify the last time the filter and fluid were changed.
Next, perform a detailed visual inspection to check the condition of the wiring for any obvious defects. Inspect the connectors and connections for security, corrosion, and damaged pins. This should include all wiring and connectors related to the transmission pressure control solenoids, transmission pump, and PCM. Depending on the configuration, the transmission pump may be electrically or mechanically driven.
Advanced Steps
The advanced steps are highly vehicle-specific and require specialized equipment to be performed accurately. These procedures necessitate the use of a digital multimeter and the specific technical references for the vehicle. It is important to obtain the specific troubleshooting guidelines for your vehicle before proceeding with the advanced steps. Voltage requirements may vary depending on the specific model of the vehicle. Fluid pressure requirements will also vary based on the transmission design and configuration.
Continuity Checks
Unless otherwise specified by the technical data, the normal readings for wiring and connections should be 0 ohms of resistance. Continuity checks should always be performed with the power removed from the circuit to avoid shorting the circuit and causing further damage. Resistance or lack of continuity indicates faulty wiring that is either open or shorted and must be repaired or replaced.
What are some common repairs for this code?
Possible misdiagnoses may include:
We hope that the information provided in this article has been helpful in guiding you towards resolving the issue with your pressure control solenoid trouble code. However, please note that this article is purely informational, and the specific technical data and service bulletins for your vehicle should always take precedence.
