P2077

P2077-INTAKE MANIFOLD TUNING VALVE POSITION SENSOR CIRCUIT LOW

For a complete wiring diagram Consult 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 below the minimum acceptable value.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

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 less than 3%?

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 Solenoid Assembly connector.
Turn the ignition on.
With the scan tool, read the MTV PWM Feedback.

NOTE: The MTV PWM Feedback should be greater than 97% with the connector disconnected.

Is the MTV PWM Feedback greater than 97%?

Yes

- Verify that there is good pin to terminal contact in the Manifold Tune Valve Assembly and Powertrain Control Module connectors. If OK, replace the Manifold Tune Valve Solenoid Assembly.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go to 3

3. (K857) 5 VOLT SUPPLY CIRCUIT VOLTAGE

Measure the voltage of the (K857) 5 Volt Supply circuit in the Manifold Tune Valve Assembly harness connector.
Is the voltage above 4.5 volts?

Yes

- Go to 7

No

- Go to 4

4. (K857) 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Turn the ignition on.
Disconnect the C1 and C2 PCM harness connectors.
Measure the resistance between ground and the (K857) 5 Volt Supply circuit in the Manifold Tune Valve Assembly harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 5

No

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

5. (K857) 5 VOLT SUPPLY CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Measure the resistance between the (K857) 5 Volt Supply circuit and the (K900) Sensor Ground circuit in the Manifold Tune Valve Assembly harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 6

No

- Repair the short between the (K857) 5 Volt Supply circuit and the (K900) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. EXCESSIVE RESISTANCE IN THE (K857) 5 VOLT SUPPLY CIRCUIT

Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
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 8

No

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

8. (K234) MTV SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Measure the resistance between the (K234) MTV Signal circuit and the (K900) Sensor Ground circuit in the Manifold Tune Valve Assembly harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 9

No

- Repair the short between the (K234) MTV Signal circuit and the (K900) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

9. EXCESSIVE RESISTANCE IN THE (K234) MTV SIGNAL CIRCUIT

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 11

No

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

11. POWERTRAIN CONTROL MODULE (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. Verify that there is good pin to terminal contact in the Manifold Tune Valve Assembly and Powertrain Control Module connectors.
Search for 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.