P1028

P1028-CYLINDER 2 OIL SUPPLY SOLENOID VALVE OVER VOLTAGE

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

MultiAir is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; MultiAir, through the use of an electronically controlled " hydraulic link" between the camshaft and intake valve, allow for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely

The MultiAir valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.

- When Monitored:
Engine running and no battery voltage faults present.

- Set Condition:
When the Powertrain Control Module (PCM) detects that the internal Solenoid driver voltage is above 28.0 volts. One trip fault.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC
1. Start the engine and allow it to idle.

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 possible serious or fatal injury.

2. With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. CHECK THE PCM POWER AND GROUND CIRCUITS
1. Perform the CHECKING THE PCM POWERS AND GROUNDS test procedure. Component Tests and General Diagnostics.

Were any problems found?

Yes

- Perform the appropriate repair.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Solenoid and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Solenoid and the Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

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

No

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