I have a Pontiac G6 v6 3.9 .. I have a code p2078 twice.. do I have to change the intake manifold tuning valve sensor or what?
What year is it ?
DTC P2078: Intake Manifold Tuning (IMT) Valve Position Sensor Circuit High Voltage
Associated with this code or any coded is a diagnostic flow chart ,for testing of the electrical circuit's for the position sensor . If you don't know that ,an know how to test electrical circuit's ,your best bet , take it to a qualified repair . Rather then guessing an just replacing parts .
Circuit/System Description
An intake manifold tuning (IMT) valve is used to change the intake manifold plenum configuration. When the IMT valve is open, the intake manifold is configured to one large plenum. When the IMT valve is closed, the intake manifold is configured to 2 smaller plenums. The IMT valve improves engine performance at low and high engine speeds depending on the engine load. The IMT valve assembly consists of the following:
• A tuning valve
• A microprocessor
• An electric motor
• A hall-effect sensor
• An ignition voltage circuit
• A ground circuit
• An IMT valve control circuit
• An IMT valve signal circuit
P2078
The engine control module detects an open in the IMT valve ground or a continuous short to voltage in either the IMT valve signal circuit or the sensor. This diagnostic runs continuous when the conditions for running are met.
Test the electrical circuit's !!!!!!! you would need a wiring diagram
Circuit/System Testing
Ignition OFF, disconnect the IMT valve harness connector at the IMT valve.
Test for less than 1 ohm of resistance between the IMT valve ground circuit terminal B and ground.
? If greater than the specified value, test the ground circuit for an open/high resistance.
Ignition ON, verify that a test lamp illuminates between the IMT valve ignition 1 voltage circuit terminal A and ground.
? If the test lamp does not illuminate, test the IMT valve ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse for the IMT valve ignition 1 voltage circuit is open, test or replace the IMT valve.
Connect a test lamp between the IMT valve control circuit terminal C and the IMT valve ignition 1 voltage circuit terminal A.
Command the IMT valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
? If the test lamp is always ON, test the IMT valve control circuit for a short to ground. If the circuit tests normal, replace the engine control module.
? If the test lamp is always OFF, test the IMT valve control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the engine control module.
Ignition ON, test for 4-6 volts between the IMT valve signal circuit terminal D and ground.
? If less than the specified range, test the IMT valve signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the engine control module.
? If greater than the specified range, test the IMT valve signal circuit for a short to voltage. If the circuit tests normal, replace the engine control module.
Install a 3A fused jumper wire between the IMT valve signal circuit terminal D and ground. Verify the scan tool IMT valve Feedback parameter transitions from 0-100 percent.
? If parameter does not change, test the IMT valve signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the engine control module.
If all circuits test normal, test or replace the IMT valve.
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