EngineLightCodes
Powertrain code

P0218 Transmission Fluid Temperature Sensor A Over Temperature Condition

Severity
Stop soon
Typical repair cost
$90–$880
Do it yourself
Shop job
Shop time
0.5–4 hours

P0218 is a condition code: the transmission or engine module reports that transmission fluid temperature sensor A reads above an overheat limit.

How the engine computer detects it

Saab's Aisin automatic sets it above 170 °C (338 °F) for more than 10 s, or above 140 °C (284 °F) for two minutes at high speed, shows a 'transmission overheating' warning and shifts less smoothly; afterwards a fluid change is advised because the additives are spent. Ford uses its own code on diesels and lists P0218 without the warning light on other models. Reactions include earlier torque converter lock-up, a modified shift pattern and sometimes reduced power. Causes are real overheating – towing, hills, low or old fluid, a clogged cooler – or a sensor reading wrongly.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Transmission overheating warning
  • Changed or harsh shifting
  • Limp mode or reduced power possible
  • Burnt fluid smell

Common causes

  1. High load (towing, hills, sustained full throttle, stop-and-go in heat) Most likely
  2. Transmission fluid low or aged Possible
  3. Fluid cooler, thermostat or lines clogged, weak cooling system Possible
  4. Torque converter clutch slipping or internal damage Less likely
  5. Temperature sensor or wiring reading wrongly Less likely

How to diagnose P0218

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: transmission fluid temperature sensor, transmission cooler, automatic transmission.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
2
Fuel and air metering (injector circuit)
18
Specific fault

Questions drivers ask

Can I drive with code P0218?

No. Pull over as soon as it's safe and switch the engine off. An overheating engine can warp the cylinder head or blow the head gasket within minutes. Don't open the radiator cap while it's hot. Check the coolant level once it has cooled, and have the car towed if the warning comes back.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.