P2755 — Transmission Fluid Cooler Control Circuit High #

Please note: The description for DTC P2755 can vary depending on the vehicle manufacturer (OEM). Always check your specific OEM service information for the most accurate wording.

• Transmission Fluid Cooler Control Circuit High (Generic/SAE)
• Transmission Oil Cooler Control Circuit High (Toyota, Lexus)
• Transmission Fluid Cooler Valve Circuit High (GM/Chevrolet)

Summary of DTC P2755 #

The diagnostic trouble code P2755 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected a high voltage condition in the transmission fluid cooler control circuit. This circuit manages the operation of a valve or solenoid responsible for regulating the temperature of the transmission fluid, usually by controlling fluid flow through an auxiliary cooler. When the circuit voltage is higher than expected, it often points to an electrical fault such as an open circuit, a short to voltage, or a failed component. This code is most common in automatic transmissions equipped with electronically controlled cooling systems, and is particularly relevant for late-model vehicles. Ignoring this warning can lead to improper transmission cooling, risking long-term transmission damage.

Common Symptoms for Code P2755 #

Vehicles exhibiting DTC P2755 may present few to no immediate driveability issues, but there are telltale signs that should not be overlooked. The most obvious symptom is the illumination of the Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL). However, depending on the severity and the system design, you might also notice shifting anomalies or overheating indicators.

• Check Engine Light (CEL) or MIL illuminated
• Transmission overheating warnings or high temperature readings
• Erratic shifting or delayed gear engagement
• Reduced transmission performance (limp mode in some cases)
• No noticeable symptoms (in early or mild cases)

Most Likely Causes for DTC P2755 #

This code is most often triggered by an electrical issue within the transmission fluid cooler control circuit. The list below ranks the causes from most to least frequent, according to industry data and OEM technical bulletins.

1. Open circuit in the wiring harness to the transmission fluid cooler control solenoid/valve
2. Short to voltage in the control circuit wiring
3. Faulty transmission fluid cooler control solenoid or valve (internal electrical failure)
4. Poor electrical connections at the solenoid/valve or PCM/TCM connector
5. PCM/TCM failure (rare, but possible if other causes are ruled out)

Step-by-Step Diagnostic for P2755 #

A systematic approach is essential to avoid unnecessary part replacements. Use an OEM-quality scan tool and a digital multimeter (DMM) for accurate results.

• 1. Retrieve and confirm the code: Clear the code, perform a road test, and verify P2755 returns.
• 2. Visually inspect wiring: Check for damaged, chafed, corroded, or disconnected wires and connectors at the transmission fluid cooler solenoid/valve.
• 3. Check for shorts or open circuits: Using a DMM, test for continuity and for voltage in the control circuit between the PCM/TCM and the solenoid/valve.
• 4. Test the solenoid/valve: Measure resistance across the solenoid/valve terminals and compare to OEM specifications. Replace if out of range.
• 5. Inspect connectors: Look for bent pins, corrosion, water intrusion, or loose fit at all related connectors.
• 6. Check PCM/TCM operation: If wiring and solenoid/valve test good, follow OEM flowcharts to test PCM/TCM output (rarely the cause).

Possible Repairs for P2755 #

Once you identify the root cause, targeted repairs will resolve P2755 without guesswork. Always clear the code and perform a test drive after repairs to confirm success.

• Repair or replace damaged wiring/connectors in the control circuit
• Replace the transmission fluid cooler control solenoid or valve if defective
• Secure and clean all electrical connectors; apply dielectric grease as needed
• Replace the PCM/TCM only if conclusively proven faulty (last resort)

Can You Drive with Code P2755? #

Limited/Not recommended. While some vehicles may not show immediate symptoms beyond a warning light, continued driving with P2755 can put your transmission at risk if the fluid is not being properly cooled. If your vehicle enters limp mode, experiences hard shifting, or shows signs of overheating, stop driving and address the issue promptly. Short trips to a repair facility are generally safe if no symptoms are present, but avoid heavy loads or high temperatures until repairs are made.

Vehicles Most Commonly Affected by P2755 #

Based on repair industry data and OEM technical bulletins, the following vehicles are more frequently associated with DTC P2755—especially those equipped with electronically controlled transmission fluid coolers:

• Toyota Camry, Highlander, Tacoma, Tundra (2010s–present)
• Lexus RX, ES, GS (2010s–present)
• Chevrolet Silverado, Tahoe, Suburban (late 2000s–present)
• GMC Sierra, Yukon (late 2000s–present)
• Some Nissan and Infiniti models (with active transmission coolers)

Frequent Mistakes & Best Practices for P2755 #

Avoid these pitfalls to save time and money. Following industry best practices ensures an accurate diagnosis and repair.

• Replacing the solenoid/valve without checking wiring (most common error)
• Ignoring connector corrosion or loose pins
• Skipping continuity and voltage tests in the circuit
• Overlooking TSBs (Technical Service Bulletins) from the OEM with updated repair procedures
• Not performing a post-repair test drive to confirm resolution

Quick FAQ for Code P2755 #

Still have questions? Here are a couple of the most common ones:

• Q: Can a low transmission fluid level trigger P2755?
  A: No, P2755 is specifically an electrical circuit issue. However, low fluid can cause related transmission problems, so always check fluid condition and level during diagnosis.
• Q: Is this code covered under powertrain warranty?
  A: Often, yes, if the vehicle is within the OEM powertrain warranty and the fault is due to a failed component (like the solenoid/valve). Wiring repairs may or may not be covered—check with your dealer.