P0970 OBD-II Trouble Code: Pressure Control Solenoid “C” Control Circuit Low

Check Engine Light

P0970 code definition

The P0970 trouble code detects an error with one of the pressure control solenoid control circuits

What the P0970 code means

The P0970 code is a standard OBD-II trouble code that notes an error from the pressure control solenoid control circuit, specifically with regards to the “C” region of the circuit. Vehicles with automatic transmissions rely on the pressure control solenoids to regulate the hydraulic pressure in the transmission, which is used to actuate gear changes and help torque converter lockup. The pressure control solenoids are controlled by the powertrain control module (PCM), which uses engine load, engine speed, vehicle speed, and the position of the throttle to select the correct hydraulic pressure. When the PCM notes a discrepancy between the desired hydraulic pressure and the actual hydraulic pressure, the P0970 trouble code will be detected.

What causes the P0970 code?

There are a handful of potential causes for the P0970 code, including:

  • Malfunctioning pressure control solenoids
  • Insufficient transmission fluid levels
  • Dirty or contaminated transmission fluid
  • Malfunctioning high pressure pump
  • Internal transmission mechanical failures
  • Hydraulic blockages in the fluid passages of the internal transmission
  • In very rare cases, a malfunctioning PCM or transmission control module
  • Damaged electrical components, such as shorted wires or open connectors in the system

What are the symptoms of the P0970 code?

When the P0970 trouble code is detected, the Check Engine Light will likely illuminate on the vehicle’s gauge cluster. The transmission warning light may also light up, and it’s possible that the overdrive light will blink. There also may be some drivability problems involving the transmission, such as harsh shifting, transmission slippage, transmission overheating, and possibly even an inability to shift. The transmission may also enter “limp-in” mode, and the torque converter clutch could be incapable of engaging or disengaging. It is common for drivers to notice a decrease in fuel efficiency.

How does a mechanic diagnose the P0970 code?

The P0970 code will be diagnosed using a standard OBD-II trouble code scanner. A reputable mechanic will look at the freeze frame data from the scanner to assess the code and look for any additional trouble codes that are present. In the event that multiple codes have been detected, the technician should address them in the order in which they appear. The trouble codes will then need to be reset, and the vehicle should be restarted. The mechanic will then check to see if the code has returned. If it has not, it was likely erroneously detected, or the result of an intermittent error.

If the P0970 code remains on after the reset, then the mechanic should check the transmission fluid. If the fluid is low or dirty, then it can be refilled or changed. If the fluid is severely contaminated, however, the entire transmission may have to be repaired or replaced.

Next, the mechanic will visually inspect the electrical components in the system, and replace all circuits, connectors, and wires that are damaged or otherwise compromised. If the problem persists, a manual pressure gauge can be hooked up to the hydraulic pressure to assess whether or not the pressure in the system is consistent with the manufacturer’s recommendations. If the pressure is lower than it should be, there is likely a defective pressure pump, solenoid, or regulator, or a blockage problem. These components should be inspected, tested, and possibly replaced.

If the issue causing the P0970 code has still not been resolved, then the technician will have to thoroughly inspect the internal transmission, and potentially the PCM and transmission control module.

It’s important for the mechanic to reset the trouble codes and restart the vehicle after any component is replaced before continuing with the inspection. This allows the technician to know as soon as the problem has been fixed.

Common mistakes when diagnosing the P0970 code

The most commonly made mistake when diagnosing the P0970 code is the failure to properly follow the OBD-II trouble code diagnosis protocol. It’s important that the protocol always be followed exactly, to ensure that inspections and repairs are thorough, accurate, and efficient. It is common for high pressure pumps to be replaced when the only issue is a damaged electrical component.

How serious is the P0970 code?

The vehicle with a detected P0970 code may still be drivable, though it will likely have some transmission performance issues. The transmission issues may be severe enough that the car is essentially inoperable, as the car may have difficulty shifting, or may not be able to shift at all. Even if the car is drivable, damage can be done to the transmission if the issue is not taken care of. For these reasons, the P0970 code should be addressed as soon as it is detected.

What repairs can fix the P0970 code?

Possible repairs for the P0970 code include:

Additional comments for consideration regarding the P0970 code

The P0970 trouble code will often be accompanied by other drivability codes, such as torque converter clutch and shift solenoid trouble codes. Codes should always be addressed in the order in which they appear on the OBD-II trouble code scanner.

Need help with a P0970 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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