P3400
DTC P3400
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 Descriptor
DTC P3400
- Cylinder Deactivation System Performance
Diagnostic Fault Information
Circuit/System Description
The cylinder deactivation system is used to deactivate 4 cylinders of the engine under light load driving conditions. The engine control module (ECM) commands the cylinder deactivation solenoids ON to deactivate engine cylinders 1, 7, 6, and 4, switching to 4 cylinders or V4 mode. The cylinder deactivation solenoids controls the oil flow to the appropriate valve lifters. The engine operates on 8 cylinders or V8 mode, during engine starting, engine idling, and medium to heavy throttle conditions.
Ignition voltage is supplied directly to the 4 cylinder deactivation solenoids. The engine control module (ECM) controls the 4 cylinder deactivation solenoids by grounding the control circuit with a solid state device called a driver.
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 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 throttle position sensor, are not within the range of the calculated values for V4 mode.
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.
* The valve lifter oil manifold 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 (except L96) ([1][2]Electrical Diagrams)Engine Controls Schematics (L96) ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Cylinder Deactivation (Active Fuel Management) System Description (Cylinder Deactivation (Active Fuel Management) 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 (Control Module References) for scan tool information
Special Tools
EN-46999 Displacement On Demand Tester
For equivalent regional tools, refer to Special Tools (Tools and Equipment).
Circuit/System Verification
Note: The engine oil level and the oil pressure are critical to the correct operation of the Cylinder Deactivation System. Verify that the engine has the correct oil level and the correct oil pressure before continuing with this diagnostic. Refer to Oil Pressure Diagnosis and Testing (Oil Pressure Diagnosis and Testing). Inspect the Valve Lifter Oil Filter for a restriction or blockage. Refer to Valve Lifter Oil Filter Replacement (Valve Lifter Oil Filter Replacement).
1. Ignition ON, observe the scan tool DTC information. Verify that DTC P0201-P0208, P0351-P0358, P3401, P3425, P3441, or P3449 is not set.
• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.
2. Engine idling at the normal operating temperature. Verify there is no abnormal engine noise.
• If there is an abnormal engine noise, refer to Symptoms - Engine Mechanical (Symptoms - Engine Mechanical) for further diagnosis.
3. Perform the Cylinder Deactivation (Active Fuel Management) System Compression Test (Cylinder Deactivation (Active Fuel Management) System Compression Test). The Cylinder Deactivation System should pass the compression test.
4. 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, remove the valve lifter oil manifold assembly ignition fuse from the underhood fuse block.
Note: Probe each terminal at the underhood fuse block with a test lamp connected to ground to determine what terminal to connect the DMM. The test lamp should not illuminate on the circuit that needs to be tested.
2. Connect a DMM between the ignition circuit fuse terminal going to the valve lifter oil manifold assembly and the ECM housing.
3. Ignition ON, command each Cylinder 1, 4, 6, and 7 Deactivation solenoid ON and OFF with the scan tool. Verify the resistance of each solenoid is between 11-18 ohm with the solenoid commanded ON.
• If greater than the specified range for all cylinder deactivation solenoids, test the ignition circuit for an open/high resistance.
• If greater than the specified range for one or more but not all cylinder deactivation solenoids, test both the control circuit and ignition circuit for an open/high resistance or an open/high resistance in the cylinder deactivation solenoid. If the circuits and solenoid test normal replace the ECM.
4. If all circuits and components test normal, refer to Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing (Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing) for further mechanical diagnosis of valve lifter oil manifold assembly.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
2. Connect the harness that is labeled resistance from the displacement on demand (DOD) tester to the valve lifter oil manifold connector.
3. Connect the power leads from the DOD tester to B+ and ground. Test for 11-18 ohm on each valve lifter oil manifold solenoid.
• If not within the specified range for each solenoid, replace the valve lifter oil manifold assembly.
4. Test for infinite resistance between each valve lifter oil manifold circuit terminal listed and the valve lifter oil manifold housing.
• If less than infinite resistance, replace the valve lifter oil manifold assembly.
Dynamic Test
1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
2. Connect the cable that is labeled power from the displacement on demand DOD tester to the connector.
3. Connect the power leads from the DOD tester to B+ and ground.
4. Command each valve lifter oil manifold solenoid ON and OFF using the DOD tester. You should be able to hear each solenoid turn ON and OFF.
• If the function does not perform as specified, replace the valve lifter oil manifold assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Valve Lifter Oil Manifold Replacement (Valve Lifter Oil Manifold Replacement)
* Control Module References (Control Module References) for ECM replacement, setup, and programming