Inlet Manifold Temperature Sensor 1
Thermistor reading for the intake manifold is out of range.
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What it means (plain English)
The engine computer is getting a temperature reading from the intake manifold that’s either too high or too low, suggesting a problem with the temperature sensor itself or its wiring.
What the computer is actually seeing
The Engine Control Module (ECM) expects the inlet manifold temperature to be between 20°C and 100°C (68°F to 212°F) during normal operation. When it reads outside this range, it triggers the fault code.
What a healthy reading looks like
Normal inlet manifold temperature is approximately 20°C to 100°C (68°F to 212°F).
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 the inlet manifold temperature sensor wiring for breaks, shorts, or corrosion, especially at the connector. Repair as necessary.
- 22. Measure the voltage at the sensor connector with the key on (engine off). Expected voltage should be about 5 volts.
- 33. If voltage is absent, check the wiring back to the ECM for continuity and integrity. Repair any issues found.
- 44. If voltage is present, test the resistance of the inlet manifold temperature sensor: it should vary with temperature. Follow the manufacturer's specifications for resistance values.
- 55. If the sensor is out of spec, replace the inlet manifold temperature sensor and clear the fault code. Retest after replacement.
Common causes
- Faulty inlet manifold temperature sensor
- Wiring issues (broken, shorted, or corroded)
- Poor connections or damaged plugs
- Coolant or oil entering the intake manifold
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's advisable to fix this soon. This code could affect engine performance but isn’t an immediate safety concern.
Will this problem come back after I fix it?
If all wiring and connections are good and the sensor is replaced properly, it shouldn't come back.
Why does this code sometimes pair with SPN 1247 or SPN 1248?
These codes often indicate related temperature or performance issues in the intake or exhaust systems, suggesting a broader thermal management problem.
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