Engine Coolant Temperature Exceeds Normal Operating Range

The engine's coolant is getting too hot, which means the engine could overheat and cause serious damage. This usually happens when the temperature hits around 240°F (116°C).

The engine control module (ECM) is monitoring coolant temperature and expects readings between 180°F (82°C) and 220°F (104°C). If it sees values above 240°F (116°C) for a prolonged period, it sets this code.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check coolant level in reservoir; add if low. Decision: If it was low, refill and retest. If not, proceed to step 2.
2. 22. Inspect for coolant leaks around hoses, radiator, and engine. Decision: If leaks found, repair and retest. If not, proceed to step 3.
3. 33. Check thermostat operation by feeling the hoses: Upper hose should warm up as engine heats up. Decision: If it's cold or inconsistent, replace thermostat. If normal, proceed to step 4.
4. 44. Check water pump operation; look for leaks or listen for noise. Decision: If faulty, replace water pump. If pump is okay, proceed to step 5.
5. 55. Inspect radiator for blockages or damage. Decision: If blocked, clean or replace radiator. If all components are okay, there may be a problem with the ECM.

• Low coolant level
• Thermostat malfunction
• Coolant leak
• Failed water pump
• Blocked radiator

$$