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P2078 is a diagnostic trouble code (DTC) for "Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High
This code will set if the Engine Control Module (ECM), or Powertrain Control Module (PCM), detects a problem with the position of the IMT valve.
This code is set when the ECM sees a higher than expected voltage from the IMT position sensor. This can occur if the circuit has a short to power or a bad ground.
The first step would be to connect a scan tool to the vehicle's OBD II connector, check for codes and observe the scan tool data for the IMT valve. Most vehicles have the capability to command the IMT valve motor to move. This should be done while watching the scan tool data and observing the valve itself. Often times it is necessary to do some disassembly to physically check the valve and sensor.
Some IMT valves are vacuum actuated and others are electrically actuated. Vacuum lines to the vacuum actuated valves frequently plug, collapse or break. Failing to thoroughly inspect the vacuum lines can lead to misdiagnosis of the IMT valve.
Some disassembly is often necessary to see if the valve flap has broken away from its shaft. If this happens, all data and the valve motor will work, but drivability issues will still exist. A mechanic could dismiss this code as erroneous and suspect other components as the problem.
This code will likely cause drivability problems that the owner will find annoying. Outside of drivability issues this code will not cause damage to the motor or be unsafe for the passengers.
Replacing the IMT valve (the sensor that this code indicates is the problem is most often part of the IMT valve assembly and will be replaced as a single unit)
Repairing wiring to the control circuit
Repairing vacuum lines that may be plugged or leaking
This system is designed to enable better fuel mileage and performance in modern vehicles. The IMT valve directs the intake air flow from a long path at low RPM’s (Revolutions Per Minute) to a shorter path at higher RPM’s. This affects the MAF (Mass Air Flow) sensor’s data. The MAF, or as it is sometimes called, the MASS air flow sensor, is one of the primary sensors used by the ECM to calculate air/fuel ratio.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.