Excessive Intake Manifold Temperature

The engine's computer is seeing that the temperature of the air in the intake manifold is above the normal range, which can lead to poor performance or engine knock.

The engine control module (ECM) monitors the intake manifold temperature sensor voltage. This sensor typically reads between 0.5V (cold) and 4.5V (hot). When the temperature exceeds the threshold, which may be around 100°C (212°F) depending on application, a fault code is triggered.

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 the condition of the wiring and connector for the intake manifold temperature sensor. Look for frayed wires or corrosion.
2. 22. Measure the voltage at the sensor connector with the engine running. You should see 0.5V to 4.5V based on temperature. If not in this range, replace the sensor.
3. 33. If the sensor reads correctly, check the intake manifold temperature with an infrared thermometer to validate the sensor's reading. Expect temperatures of 20°C to 75°C under normal conditions.
4. 44. Inspect for any leaks in the coolant system that could cause overheating. Look for discoloration or low coolant levels. Repair as necessary.

• Faulty intake manifold temperature sensor
• Wiring issues (shorts or opens) to the sensor
• Coolant leaks leading to overheating
• Excessive fuel delivery causing increased combustion temperatures

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