P2078

P2078-INTAKE MANIFOLD TUNING VALVE POSITION SENSOR CIRCUIT HIGH

For a complete wiring diagram refer to Diagrams/Electrical

- When Monitored:

With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:

The PCM detects that the PWM signal from the Manifold Tune Valve Position sensor is above the maximum acceptable value.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. MTV PWM FEEDBACK

Start the engine and allow it to reach normal operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.

With the scan tool, read the MTV PWM Feedback.

Is the MTV PWM Feedback greater than 97%?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

2. MANIFOLD TUNE VALVE ASSEMBLY

Turn the ignition off.

Disconnect the Manifold Tune Valve Assembly connector.

Connect a jumper wire between the (K900) Sensor Ground circuit and the (K234) MTV Signal circuit in the Manifold Tune Valve Assembly harness connector.

Turn the ignition on.

With the scan tool, read the MTV PWM Feedback.

NOTE: The MTV PWM Feedback should be less than 3% with the jumper wire in place.

Is the MTV PWM Feedback less than 3%?

Yes

- Replace the Manifold Tune Valve Assembly.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. (K857) 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.

Disconnect the C1 and C2 PCM harness connectors.

Turn the ignition on.

Measure the voltage of the (K857) 5 volt Supply circuit in the Manifold Tune Valve Assembly harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K857) 5 volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (K234) MTV SIGNAL CIRCUIT SHORTED TO VOLTAGE

Measure the voltage of the (K234) MTV Signal circuit in the Manifold Tune Valve Assembly harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K234) MTV Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. (K234) MTV SIGNAL CIRCUIT SHORTED TO THE (K857) 5 VOLT SUPPLY CIRCUIT

Measure the resistance between the (K234) MTV Signal circuit and the (K857) 5 volt Supply in the Manifold Tune Valve Assembly harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (K234) MTV Signal circuit and the (K857) 5 volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. (K234) MTV SIGNAL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (K234) MTV Signal circuit in the Manifold Tune Valve Assembly harness connector.

Is the resistance above 100 ohms?

Yes

- Go To 7

No

- Repair the short to ground in the (K234) MTV Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. (K234) MTV SIGNAL CIRCUIT OPEN

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K900) Sensor Ground circuit between the Manifold Tune Valve Assembly harness connector and the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 9

No

- Repair the open in the (K900) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

9. PCM

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Manifold Tune Valve Assembly and the Powertrain Control Module (PCM).

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

Look for the data to change or for the DTC to reset during the wiggle test.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module (PCM).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test