HomeTrouble CodesP2755

P2755 — Transmission Fluid Cooler Control Circuit High

Manufacturer-specificPowertrain (engine & transmission)

Code P2755 indicates that the powertrain control module has detected a higher than expected voltage in the transmission fluid cooler control circuit. This typically points to an electrical fault in the system that manages transmission fluid temperature, such as a short to power or a failed control component.

Symptoms

What causes it — most likely first

1. Failed cooler control solenoid or relay

The internal switch or relay that controls the transmission fluid cooler can short internally, causing a continuous high voltage condition on the control circuit.

2. Wiring short to voltage

Chafed, melted, or damaged wiring in the control circuit can short to a power source, sending excessive voltage to the control module and triggering the code.

3. Poor electrical connection

Corroded, pushed back, or loose terminals in the circuit connectors can alter resistance and cause abnormal voltage readings.

4. Failed transmission fluid cooler pump

On vehicles equipped with an electrically driven auxiliary cooler pump, an internal short in the pump motor can cause this high voltage code.

5. Faulty PCM or TCM

A failure in the internal driver of the powertrain or transmission control module is possible but rare, occurring only if it cannot properly regulate the circuit voltage.

How it's diagnosed

  1. Scan the vehicle for all stored codes and review freeze frame data to understand the operating conditions when the code was set.
  2. Perform a visual inspection of the cooler control circuit wiring, connectors, and relay for obvious damage, chafing, or corrosion.
  3. Test the transmission fluid cooler control solenoid or relay for proper resistance and operation according to manufacturer specifications.
  4. Use a multimeter to check for a short to voltage or a short to ground in the control circuit wiring between the control module and the component.
  5. Clear the codes and test drive the vehicle to verify if the condition returns before replacing any parts.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

What does 'Circuit High' mean for this code?

It means the control module is detecting voltage on the control circuit when it expects the circuit to be off or at a lower voltage, usually indicating a short to power or a failed component.

Is it safe to drive with code P2755?

It is risky. The transmission fluid cooler may not operate, leading to transmission overheating, which can cause severe internal transmission damage.

Does this code mean my transmission is failing internally?

No, this is an electrical circuit code related to the cooler control system, not a mechanical failure inside the transmission itself.

Do I need to replace the PCM or TCM to fix P2755?

Rarely. Although some mechanics or sources may prematurely suggest the computer is bad, the cause is almost always a failed solenoid, relay, or a wiring issue. The control module should be the absolute last component tested and replaced.