P2077 OBD-II Trouble Code: Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit Low

P2077 code definition

Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit Low

What the P2077 code means

P2077 is an OBD-II generic code for the Engine Control Module (ECM), detecting the intake manifold tuning valve position sensor circuit Pulse Width Modulation (PWM) below specifications or expected values.

What causes the P2077 code?

• The ECM monitors the return voltage PWM from the IMT sensor circuit and will turn on the Check Engine Light and set code P2077 when the PWM voltage return is below the specified voltage for the position commanded.

• A short to ground on the 5 volt reference supply to the IMT sensor

• An open wire on the power supply circuit

• An open or short on the return signal wire to the ECM

• High resistance in the signal return wire circuit

• Corrosion in the connections

What are the symptoms of the P2077 code?

• The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.

• The engine may have low power on acceleration, if the IMT is closed when it failed.

• The engine may have low power at higher speeds, if the IMT failed in the open position.

• The engine may hesitate on acceleration, depending on what position the IMT failed.

How does a mechanic diagnose the P2077 code?

• Scan codes and document the codes in the ECM and look at the freeze frame data for failure.

• Look at the data for the IMT to see if it changes position on acceleration and cruise speeds.

• Measure the resistance of the IMT sensor and check to specifications.

• Diagnose code P2077 following the manufacturer pinpoint tests.

• Check the wiring and connector to the supply circuit for shorts, breaks or loose connections to the IMT sensor.

• Verify the IMT actuator mechanism is not binding in the intake manifold.

Common mistakes when diagnosing the P2077 code?

• Clearing the ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired.

• Failing to clear the ECM codes after the codes are fixed.

• Failing to use the special connector probe tool when testing the connectors and causing female connector damage.

How serious is the P2077 code?

Code P2077 is for the intake manifold runner control and the runner changes to increase power at low RPMs and changes again to give better highway mileage. Problems with this system will cause the engine to have low power and lower fuel mileage on the highway.

What repairs can fix the P2077 code?

• [Replace the intake manifold runner control sensor].(https://www.yourmechanic.com/services/intake-manifold-runner-control-replacement)
• Repair an open or short in the IMT wiring or connector.
• Replace the intake manifold runner actuator.
• Replace the intake manifold for stuck manifold valves.

Additional comments for consideration regarding the P2077 code

Code P2077 is for vehicles that have an intake manifold runner to shorten or lengthen the runners by operating a set of valves built into the intake manifold. The runner is operated by electrical or vacuum style actuators and have sensors built into them. The sensors could have separate parts depending on manufacturer. Follow pinpoint tests for this reason.

Need help with a P2077 code?

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