P0714

What it means

P0714 is the generic code for an intermittent fault in the transmission fluid temperature sensor A circuit. The transmission control unit saw the sensor signal jump, drop out or read implausibly for a moment, for example a sudden swing from normal to open or short circuit, and then return to normal. Because the fault comes and goes, it is often linked to a wiring, connector or sensor contact problem.

Symptoms

• Gearbox warning light or malfunction indicator lamp on
• Gearbox goes into limp mode or fixed gear now and then
• Harsh, delayed or erratic gear changes
• Torque converter lock-up not working or cycling
• Temperature reading on a scan tool jumping about or dropping to an extreme value
• Fault appears and disappears, often with vibration or when the gearbox is hot

Possible causes

• Damaged, chafed or corroded wiring to the fluid temperature sensorlikely
• Loose, corroded or contaminated connector at the sensor or the gearbox harness pluglikely
• Failing transmission fluid temperature sensor with an intermittent internal faultlikely
• Fluid leaking along the harness into the connector, or contaminated or degraded fluid affecting the sensorpossible
• Poor earth or reference voltage supply shared with other gearbox sensorspossible
• Internal valve body or wiring loom fault, on designs where the sensor is part of the internal harnesspossible
• Fault in the transmission control unit itselfrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting temperature, speed and load when the fault set, and check for other gearbox or communication codes.
2. Check the fluid level and condition as the procedure for that model requires, looking for burnt smell, debris or heavy contamination.
3. Inspect the gearbox wiring and connectors visually for chafing, heat damage, oil or fluid inside the plug, bent pins and corrosion.
4. With a scan tool, watch the live fluid temperature while gently wiggling the harness and connector and tapping the sensor area; a sudden jump or dropout points to wiring or the sensor.
5. Check that the temperature reading rises smoothly and plausibly from cold to warm and agrees with other temperature readings after a cold soak.
6. Measure the sensor circuit with a multimeter against the manufacturer data: reference voltage, earth integrity, resistance of the sensor and continuity of the wiring, checking for voltage drop.
7. Check the control unit connector and earths, and look for software updates or technical bulletins for your model.
8. If the sensor is inside the gearbox, the location and test procedure depend on the model and gearbox type, so follow the manufacturer's procedure before dismantling anything.

How to fix

• Repair or replace damaged wiring and use proper sealed connections rather than temporary joins.
• Clean, re-seat or replace corroded or loose connectors and terminals, and cure any fluid leak into the plug.
• Replace the fluid temperature sensor or the internal harness or sensor assembly if tests show it is faulty, as the model design requires.
• Correct fluid level or replace degraded fluid using the specified type if contamination is found.
• Repair poor earths or supply faults, and update the control unit software only if a known issue is listed for that vehicle.

Can I keep driving?

Nearby codes

• P0713GenericTransmission Fluid Temperature Sensor A Circuit High
• P0715GenericInput/Turbine Shaft Speed Sensor A Circuit