For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P3400: Cylinder Deactivation System Performance

### Circuit/System Description

The Cylinder Deactivation System Performance diagnostic is a test of the internal mechanical condition of the engine, during operation in V4 mode. The engine control module (ECM) determines the internal mechanical condition of the engine through the actual measured values of the mass airflow (MAF) sensor, the intake manifold absolute pressure (MAP) sensor, and the throttle position (TP) sensor. The actual measured values of the 3 sensors are then compared to the calculated values for V4 mode, stored in the ECM. If the measured values are incorrect for V4 mode, the ECM will set DTC P3400, and will return to V8 mode operation.

### Conditions for Running the DTC

• | DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0119, P0335, and P0336 are not set.

• | The engine speed is between 450-6,400 RPM.

• | The IAT Sensor parameter is between -7 and +125°C (+19 and +257°F).

• | The ECT Sensor parameter is between 70- 125°C (158-257°F).

• | Time in V8 mode is more than 2 seconds.

• | Time in V4 mode is more than 2 seconds.

• | This DTC runs continuously within the enabling conditions.

### Conditions for Setting the DTC

• | The ECM detects that the actual measured values from the MAF sensor, MAP sensor, and TP sensor, is not within the range of the calculated values for V4 mode.

• | The above condition is met for more than 100 milliseconds.

### Action Taken When the DTC Sets

• | DTC P3400 is a Type B DTC.

• | The engine will return to V8 mode.

### Conditions for Clearing the DTC

DTC P3400 is a Type B DTC.

### Diagnostic Aids

• | This DTC will not set during engine idling conditions. The vehicle will need to be driven for the DTC to set.

• | This test procedure requires that the vehicle battery has passed a load test and its completely charged. Refer to Battery Inspection/Test.

• | The valve lifter oil manifold (VLOM) solenoids are assigned to the following engine cylinders:

- | Solenoid #1--Cylinder #1

- | Solenoid #2--Cylinder #4

- | Solenoid #3--Cylinder #6

- | Solenoid #4--Cylinder #7

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cylinder Deactivation (Active Fuel Management) System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Start and idle the engine.
2. Allow the engine to reach normal engine operating temperature. The engine should idle smoothly, without any misfires. If the engine misfires, refer to DTC P0300-P0308.
3. Monitor the cylinder deactivation system data parameters with a scan tool.
4. Road test the vehicle under light throttle and load conditions that will allow the engine to command V4 mode. If all enabling conditions are met for cylinder deactivation, and if no internal engine hydraulic/mechanical fault conditions are present, the ECM will continue with V4 mode operation.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

#### Electrical System Testing

1. If DTCs P3401, P3425, P3441, or P3449 are set, refer to DTC P3401, P3425, P3441, or P3449.
2. Ignition ON, the engine OFF, command each VLOM solenoid ON and OFF using the scan tool output control function. While standing next to the engine compartment, you should be able to hear the solenoid energize and de-energize with each scan tool output control command.

⇒ | If you cannot hear each solenoids energize and de-energize, then refer to Cylinder Deactivation (Active Fuel Management) System Diagnosis.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.