P0746 OBD-II Trouble Code: Pressure Control Solenoid Performance or Stuck Off

P0746 code definition

The P0746 code appears when the PCM detects an irregularity in the electronic pressure control solenoid circuit.

What the P0746 code means

With an automatic transmission, varying amounts of hydraulic pressure are used to provide torque converter lockup and shift actuation. The exact degree of pump pressure that’s considered sufficient will differ across every make and model – often by a lot. That’s because the amount required is based on things like vehicle speed, engine speed, engine load and throttle position.

Nonetheless, code P0746 will occur when the required amount of fluid pressure doesn’t match the actual amount that is detected by the vehicle’s PCM. Usually, a Check Engine Light will come on too, but this is another element that differs across all makes and models. For some, this type of incident has to repeat more than once before the light will come on.

What causes the P0746 code?

The P0746 code could be caused by any of the following:

• A faulty electronic pressure control solenoid
• Mechanical issues with the transmission
• A blockage inside the fuel passages of the internal transmission
• Low levels of transmission fluid
• Contaminated transmission fluid
• A faulty transmission control module
• A faulty PCM (this is a very rare occurrence though)

What are the symptoms of the P0746 code?

There are no set symptoms that always occur in regards to the P0746. In fact, some drivers don’t report any noticeable symptoms at all. Other drivers will have to put up with the torque converter clutch not engaging/disengaging. Their ability to shift may also be greatly limited or even disabled altogether. When the engine idles or is coming to a stop, it could stall out.

Other common symptoms include:

• Decreased fuel efficiency
• Transmission overheating
• Harsh shifting
• Transmission slippage

A number of other trouble codes are associated with P0746. These codes are related to issues with things like converter clutch, shift solenoid, gear ratio, etc.

How does a mechanic diagnose the P0746 code?

An OBD-II scanner will first be used by your mechanic to figure out which codes have been stored. Then, they’ll check on the transmission pressure present. After that, they’ll look at the transmission fluid for signs it’s contaminated (or just that more is needed). If the fluid smells like it has burned, they’ll need to inspect the transmission pan.

Your mechanic will also want to look at all the wires that assist the pressure control solenoid. Other electrical components, like the connectors, will be important to inspect too. The high pressure pump will need to go through examination as well.

Common mistakes when diagnosing the P0746 code

Although it’s important to inspect, the high pressure pump is too often blamed for the entire code and thus replaced hastily without enough thought being given to the process. Instead, wiring malfunctions and faulty electronic pressure control solenoids are far more likely to be responsible for a P0746 code. This should serve as a reminder to carry out a thorough diagnosis before proceeding with any permanent measures.

How serious is the P0746 code?

The code doesn’t necessarily represent anything dangerous or a problem that will seriously damage your vehicle if it isn’t addressed right away. However, as you’ll notice from the symptoms above, it’s possible that your transmission may eventually overheat or your clutch won’t engage. These could have expensive ramifications and, if nothing else, may lead to much worse problems down the line, so it’s a good idea to have this code dealt with ASAP.

What repairs can fix the P0746 code?

The following may be necessary to repair your vehicle:

• Replace/repair a defective pump
• Adjust the transmission fluid level
• Replace contaminated transmission fluid
• Replace the faulty line pressure solenoid valve
• Fix the electrical connection to the line pressure solenoid valve circuit

Additional comments for consideration regarding the P0746 code

As a number of other codes may accompany this one, it’s important that you deal with them in the order they were stored so you don’t miss anything.

Need help with a P0746 code?

If your vehicle needs repairs, let YourMechanic Help. Just complete this online form or call us up at 1-800-701-6230. We’ll give you a free quote and send a certified mechanic to your place of work or home – whichever is most convenient.