What it means
Voltage on the transmission fluid cooler control line is above the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The transmission fluid cooler control circuit connects the controller to a cooling valve or fan. P2755 means the circuit voltage is higher than expected, which can happen when the control wire contacts battery power, the solenoid coil is open or a connector has poor contact.
Common causes
Most likely first.
- Control wire shorted to B+
- Open solenoid coil
- Connector pins corroded - high contact resistance
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and review cooler-control command and transmission fluid temperature readings, if available, to identify when the high-circuit fault occurred.
- Inspect the cooler control connector and harness for chafing, moisture, corrosion, loose terminals or contact with a power wire.
- Following the manufacturer's procedure, check whether the control wire is shorted to battery power.
- Test the cooler control solenoid coil for an open circuit and inspect its connector contacts for excessive resistance.
- If the wiring and solenoid pass, test the controller output and circuit operation using the manufacturer's procedure.
Common fixes
- Repair a control wire shorted to battery power or damaged by chafing.
- Clean and secure cooler control connector terminals with poor contact.
- Replace the cooler control solenoid if its coil is open.
- Repair a high-circuit fault identified at the controller connection.
Can I keep driving?
Avoid towing and heavy-load driving until the fault is diagnosed, since cooler operation may be affected and fluid temperature can rise. Stop if the transmission slips, shudders or develops missing shifts, and arrange inspection.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.