P2078
DTC P2076, P2077, or P2078
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
DTC Descriptors
DTC P2076 00
- Intake Manifold Tuning Control Valve Position Sensor Performance
DTC P2077 00
- Intake Manifold Tuning Control Valve Position Sensor Circuit Low Voltage
DTC P2078 00
- Intake Manifold Tuning Control Valve Position Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
An intake manifold tuning valve is used to change the intake manifold plenum configuration. When the intake manifold tuning valve is open, the intake manifold is configured to one large plenum. When the intake manifold tuning valve is closed, the intake manifold is configured to two smaller plenums. The intake manifold tuning valve improves engine performance at low and high engine speeds.
Ignition voltage is supplied directly to the intake manifold tuning valve solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.
The intake manifold tuning valve also contains a position sensor which is used to detect the actual position of the intake manifold tuning valve in relation to its commanded position. The ECM supplies the intake manifold tuning valve position sensor with a 5 V signal circuit and the position sensor uses a common ground circuit. The position sensor enables the ECM to detect a physically broken or stuck intake manifold tuning valve.
Conditions for Running the DTC
* The ignition is ON or the engine is operating.
* The intake manifold tuning valve solenoid has been commanded ON and OFF at least once during the ignition cycle.
* These DTCs run continuously once the above condition is met.
Conditions for Setting the DTC
The ECM detects that the commanded state of the Intake Manifold Tuning driver and the position sensor signal do not match for greater than 4 s, or for cumulative of 50 s.
Action Taken When the DTC Sets
DTC P2076 00, P2077 00, and P2078 00 are Type B DTCs.
Conditions for Clearing the DTC
DTC P2076 00, P2077 00, and P2078 00 are Type B DTCs.
Diagnostic Aids
If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool circuit test status parameters for the component. A circuit test status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Air Intake System Description (Air Intake System)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Engine idling, command the Intake Manifold Tuning solenoid ON and OFF with a scan tool. You should hear and feel an audible click.
• If no audible click is heard, refer to Intake Manifold Runner Control System Diagnosis (Intake Manifold Runner Control System Diagnosis).
2. Observe the DTC information with a scan tool. DTC P2077 00, P2077 00, or P2078 00 should not be set.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector of the Q22 Intake Manifold Tuning Solenoid Valve.
2. Test for less than 5 ohm between the ground circuit terminal 3 and battery ground.
• If greater than the specified range, test for an open/high resistance in the ground circuit.
3. Ignition ON, test for 4.8-5.2 V between the Q22 Intake Manifold Tuning Solenoid Valve signal circuit terminal 1 and ground.
4. Ignition ON, command the Intake Manifold Tuning Control Valve Solenoid Open and Closed with a scan tool. The test lamp should turn ON when the solenoid is commanded Closed, and OFF when the solenoid is commanded Open.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
5. If all circuits test normal, test or replace the Q22 Intake Manifold Tuning Solenoid Valve.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning)for ECM replacement, setup, and programming