P0711

What it means

P0711 is the generic code for the transmission fluid temperature sensor A circuit range or performance fault. The transmission control unit has seen a temperature signal that does not behave plausibly, for example it stays fixed, changes too slowly or too quickly, or does not agree with expected warm-up based on running time, engine coolant temperature or load. The signal is still within the electrical limits, so this is a plausibility fault rather than a plain open or short circuit.

Symptoms

• Gearbox warning light or engine management light on
• Harsh, delayed or flared gear changes, especially when cold
• Torque converter lock-up not engaging or engaging late
• Transmission stuck in limp mode or a fixed gear
• Poor fuel economy
• Fixed or implausible transmission temperature reading on a scan tool

Possible causes

• Faulty transmission fluid temperature sensor reading out of range or responding sluggishlylikely
• Damaged wiring, corroded terminals or poor connector contact in the sensor circuit, causing high resistancelikely
• Incorrect, degraded or contaminated transmission fluid, or wrong fluid level, affecting sensor readings and temperature behaviourpossible
• Fluid leak or internal wear causing overheating or abnormal temperature risepossible
• Faulty internal wiring harness or valve body connector (depends on the transmission design, where the sensor is often built into the internal harness or solenoid pack)possible
• Fault in the transmission control unitrare
• Outdated control unit software that mishandles the temperature model (only where the manufacturer has issued an update for this)rare

How to diagnose

1. Read all stored and pending codes and freeze frame data, noting temperature, vehicle speed and engine load when the code set
2. Check the transmission fluid level and condition (colour, smell, debris) following the manufacturer's procedure, as the method varies by model
3. Inspect the wiring and connectors between the transmission and control unit for chafing, water ingress, corrosion and bent or pushed-back pins
4. Compare live transmission fluid temperature with engine coolant temperature on a cold start; they should be close, then the fluid temperature should rise steadily
5. Watch live data during a road test or warm-up for flat-lining, sudden jumps or readings that fall while the transmission is working
6. Measure sensor resistance at the connector and compare it with the manufacturer's temperature-resistance values for that model
7. Check the circuit for continuity, short to earth or voltage, and unwanted resistance, and test the reference supply and earth
8. Check for any technical service information or software updates relating to this code for the vehicle

How to fix

• Replace the transmission fluid temperature sensor or the part it is integrated into, as specified for the model
• Repair or replace damaged wiring and clean or renew corroded connector terminals
• Correct the fluid level and renew degraded or incorrect fluid with the specified type
• Repair any leak and investigate the cause of overheating, such as a restricted cooler or internal wear
• Replace the internal harness or valve body connector where it has been proven faulty
• Update the control unit software only if the manufacturer lists an update for this fault, or repair or replace the unit if proven faulty

Can I keep driving?

Nearby codes

• P0710GenericTransmission Fluid Temperature Sensor A Circuit
• P0712GenericTransmission Fluid Temperature Sensor A Circuit Low