Intake Manifold Pressure Sensor Voltage Too High

Inside the engine’s computer, the sensor that measures pressure in the intake manifold is reporting a voltage too high, which usually indicates a problem with the sensor or wiring, potentially over 4.5V when it should be under that.

The engine control module (ECM) sees a voltage from the manifold pressure sensor that exceeds its normal operating range of around 0.5 to 4.5 volts, typically when the engine is running under load.

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. 1Check the wiring and connector at the intake manifold pressure sensor for any visible damage or corrosion.
2. 2Measure the voltage at the intake manifold pressure sensor with the key on and engine off. It should be under 0.5V in a no-load condition.
3. 3Start the engine and observe the voltage while monitoring the manifold pressure sensor knife edge (1500 RPM). Voltage should track manifold pressure typically under 4.5V.
4. 4If voltage is over 4.5V, replace the intake manifold pressure sensor and clear the code.
5. 5If the new sensor reads correctly, check the wiring again for shorts or breaks.

• Faulty intake manifold pressure sensor
• Wiring issues (short to power) causing high voltage
• Bad ECM causing incorrect signal interpretation
• Vacuum leaks affecting manifold pressure readings

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