P0751 code definition
The P0751 code indicates that the car’s computer has noted a malfunction or incorrect operation with shift solenoid A.
What the P0751 code means
Automatic transmissions use solenoids to move fluid through interior channels and create the pressure needed to change gears. The P0751 code means that there has been a problem with shift solenoid A, as opposed to shift solenoid B, which would be indicated with a P0755 code. If the computer detects a difference in the actual gear ratio as compared to the gear ratio predicted by the engine speed, throttle position and other factors, it will set the P0751 code.
What causes the P0751 code?
As with the P0755 code, there are multiple potential causes for the P0751 code. These include the following:
- Faulty shift solenoid A
- Internal blockages in the transmission preventing fluid from flowing
- Low transmission fluid
- Dirty or contaminated transmission fluid
- Internal mechanical transmission failure
- Failed PCM (rare)
- Failed TCM (rare)
What are the symptoms of the P0751 code?
The symptoms of the P0751 code mirror those of the P0755 code, and include the following:
- No discernible symptoms
- Transmission slipping
- Harsh shifting
- Transmission overheating
- Reduced fuel efficiency
- Check Engine light on
- Inability to shift into or out of gear
- Transmission stuck in “limp-home” mode
How does a mechanic diagnose the P0751 code?
Diagnosing the cause of the P0751 code begins by connecting an OBD II scanner to the car’s communication port. The mechanic will read all the codes stored in the computer and then clear them. A test drive is necessary to make sure the code resets.
Next, the mechanic should check the transmission fluid level. If it is low, it will need to be topped off and the car test driven again. If the fluid is burned or contains finings or other contamination, an inspection of the fluid in the pan will be required, and it may indicate the need for a transmission rebuild.
If the problem is not fluid related, the mechanic will need to inspect the shift solenoid wiring harness, connections and circuit for damage or corrosion. If the problem does not lie in these areas, the shift solenoid itself will need to be tested.
Common mistakes when diagnosing the P0751 code
Most commonly, mechanics will replace shift solenoid A without conducting a full diagnosis. While a failed solenoid is often the culprit, there are other factors that must be ruled out. Often, low transmission fluid is the problem.
How serious is the P0751 code?
The P0751 code is very serious, as it can affect the drivability of your car and can lead to serious transmission damage and high replacement costs if not handled promptly. Have the problem diagnosed as soon as possible.
What repairs can fix the P0751 code?
Repairing the P0751 code may require a number of different fixes depending on the actual underlying problem. They include:
- Topping off the transmission fluid
- Draining and refilling the transmission fluid
- Replacing shift solenoid A
- Repairing or replacing the wiring harness
- Cleaning corrosion from connections
Additional comments for consideration regarding the P0751 code
Determining an accurate diagnosis for the P0751 code can require a significant amount of testing and inspection. However, it is essential that a mechanic not simply replace shift solenoid A immediately, as this can lead to an expensive repair that does not solve the problem. A full diagnosis must be provided, including inspecting the wiring harness and connections.
Need help with a P0751 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.