Engine Coolant Temperature Sensor High
The YANMAR-P0118 (Yanmar) diesel fault code means: Engine Coolant Temperature Sensor High. This is a moderate severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- beginner
- Estimated cost
- $40-$200
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Common Symptoms
- False overheat warning / derate
Probable Causes (Ranked by Likelihood)
- Open ECT sensor wire Likely
- Failed ECT sensor biased high Possible
Step-by-Step Diagnostic Procedure
Scan ECT sensor voltage; should show coolant temp.
Ohm-test sensor cold and hot.
Frequently Asked Questions
What is Yanmar code P0118?
Yanmar P0118: Engine Coolant Temperature Sensor High. This code is reported on Yanmar equipment running the described engine family.
Can I keep working with Yanmar code P0118?
Do not continue operating. Risk of engine damage or unsafe shutdown.
How much does Yanmar P0118 cost to fix?
Typical repair cost: $40-$200. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.
P0118 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown: