Engine Coolant Temperature Above Normal Operating Range
Indicates that the engine coolant temperature is higher than the normal range.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
When the engine coolant gets hotter than normal, it can lead to overheating and damage. Normally, the coolant temperature should be between 180°F and 220°F. This code triggers when the temperature exceeds around 230°F.
What the computer is actually seeing
The engine control unit (ECU) monitors the coolant temperature sensor's voltage, which should typically be between 0.5V (cold) and 4.5V (hot). A value above the calibrated limit triggers this code.
What a healthy reading looks like
Coolant temperature should be 180°F to 220°F. Voltage from the coolant sensor should be between 0.5V and 4.5V.
Guided diagnostic — the DiagCoach way
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.
- 11. Check coolant level in the reservoir. If low, refill and retest. (Decision: If levels are okay, proceed to step 2.)
- 22. Inspect the coolant temperature sensor connector for corrosion or damage. (Decision: If damaged, repair/replace connector and retest.)
- 33. Measure the temperature at the thermostat housing and compare it to the sensor reading. Use an infrared or contact thermometer. (Decision: If readings are consistent, proceed to step 4.)
- 44. Check for leaks around hoses, radiator, and water pump. (Decision: If leaks are found, repair and retest.)
- 55. If no leaks are found and symptoms persist, replace the coolant temperature sensor and retest the system. (Decision: If replaced and code returns, check wiring and ECM.)
Common causes
- Faulty coolant temperature sensor
- Low coolant level
- Coolant leaks
- Thermostat stuck closed
- Faulty radiator or cooling fan
- Electrical wiring issues
- Failed water pump
Typical repair cost
$100-$300
Related codes
Frequently asked questions
Can I still drive the vehicle if this code is present?
You can drive it short distances, but be cautious of overheating; fix soon to avoid damage.
Will the code come back after repair?
If repairs are done correctly and there are no other underlying issues, it shouldn't return.
Does this code relate to cooling systems only?
Primarily, yes, but watch for overall engine performance issues that could indicate deeper problems.
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