P122D

DTC P122D

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)provide an overview of each diagnostic category.

DTC Descriptors
DTC P122D
- Intake Air (IA) Flow Position Sensor Exceeded Learning Limit

Circuit/System Description

The throttle body is a normally open valve and is only operated during DPF regeneration and when maintaining the selective catalyst reduction temperature. The position of the valve is controlled by the Engine Control Module (ECM). The throttle body system uses a a motor to move the valve to an open or closed position and a position sensor located within the valve assembly is used to monitor the position of the valve.

Conditions for Running the DTC

* DTC P02E0 or P02EB is not set.
* The ignition is ON.
* Offset learning for the throttle valve was successful in the previous driving cycle.
* The battery voltage is greater than 8 V.
* DTC P122D runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the difference between the desired throttle valve position and the actual throttle valve position is greater than 10 % or less than -10 %.

OR

The ECM detects that the learned throttle valve offset position at open or closed position is greater than 20 % or less than -20 %.

OR

The ECM detects that the difference between the maximum and minimum throttle valve position learned at open or closed position is greater than 30 %.

Action Taken When the DTC Sets

DTC P122D is a Type B DTC.

Conditions for Clearing the DTC

DTC P122D is a Type B DTC.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
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 (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information. DTC P02E2, P02E3, P02EB, P0697, P122C, P122E, or P122F should not be set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.

2. Ignition ON, command the Intake Air Flow Valve Motor between 0-100 % with a scan tool. The IAF Valve Desired Position parameter and the IAF Valve Position parameter should match.
3. Engine idling, observe the scan tool IAF Valve Pos. Sensor voltage parameter. The reading should be between 3.7-4.7 V.
4. Turn OFF the ignition while observing the scan tool IA Flow Valve Position parameter. The parameter should fluctuate between 0-100 % several times.
5. 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

Ignition OFF, inspect the Q38 throttle body for the following conditions:

* A throttle blade that is not in the rest position
* A throttle blade that is binding open or closed
* A throttle blade that opens or closes without spring pressure
* Throttle body for dirt, debris or coking
* A damaged throttle valve blade or shaft

• If a condition is found, clean or replace the Q38 throttle body as necessary.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Throttle Body Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for ECM replacement, programming and setup.