Powertrain, generic (extended)

P2755 Transmission Fluid Cooler Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

With P2755 the module sees a high level on the cooler actuator line at a moment when its driver should pull it down, the signature of a short to battery voltage or of a low-side driver that no longer switches. The cooling valve then either cannot be activated or stays energised all the time. No manufacturer publishes P2755; the component is the same one that Audi diagnoses on the 2023 Q7 and SQ7 under the open-circuit code P2753, and CARB treats such outputs as monitored comprehensive components. A damaged harness rubbing against a powered wire, a defective valve with an internal short to its supply pin, or a failed output transistor are the usual findings. Unlike P2754 a fuse rarely blows, so the fault can persist unnoticed until fluid temperatures drift.

Likely causes

Control wire shorted to a battery-voltage line
Valve internally shorted to its supply terminal
Module output transistor no longer switching

Symptoms

  • Check engine lamp on
  • Cooling valve permanently on or off
  • Slower warm-up of the transmission in cold weather

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–400
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

trans fluid cooler valvewiring harness

Related codes

P2753P2754P0218

References: law.cornell.edu, static.nhtsa.gov.