P0505

DTC P0505

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 P0505
- Idle Control System

Circuit/System Description

The powertrain control module (PCM) uses input from several engine sensors in order to determine the correct engine speed at idle. With the desired idle speed calculated, the PCM determines the correct throttle opening and the corresponding throttle position (TP) needed to obtain the desired engine speed. The PCM sends the desired throttle position or target value to the TAC module. The TAC module achieves the desired throttle position by commanding the throttle control motor to position the throttle valve at the target value. If necessary, the PCM adjusts the target throttle position in order to achieve the desired engine idle speed.

Conditions for Running the DTC

* DTCs P0011, P0012, P0031, P0032, P0100, P0101, P0102, P0103, P0115, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0171, P0172, P0220, P0222, P0223, P0300-P0304, P0335, P0339, P0340, P0341, P0351-P0354, P0500, P2102, P2103, P2111, P2112, P2118, P2119, P2120, P2121, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
* The battery voltage is greater than 11 volts.
* The engine coolant temperature is greater than 75°C (167°F).
* The engine is running at idle conditions.
* Vehicle speed has exceeded 10 km/h (6 mph) greater than once this drive cycle.
* DTC P0505 runs once per ignition cycle when the above conditions have been met.

Conditions for Setting the DTC

* The observed engine speed at idle is 100 RPM less than the expected engine speed.
OR
* The observed engine speed at idle is 150 RPM greater than the expected engine speed.
* Either of the above conditions has occurred 5 times or greater this ignition cycle.

Action Taken When the DTC Sets

DTC P0505 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0505 is a Type B DTC.

Diagnostic Aids

With the engine idling at a normal operating temperature and all accessories OFF, monitor the following parameters on the scan tool:

* TP sensor-8 to 13 percent
* Engine speed-650 to 750 RPM
* Electrical load-NO
* Commanded A/C-OFF
* Engine load-11 to 20 percent
If any of the above parameters are outside of the typical value as indicated, inspect for the cause and repair as necessary.

Operate the vehicle with the Check Mode diagnostic enabled. Refer to Service Bay Test (Service Bay Test).

Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
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 DTC information with a scan tool.

• If there are any throttle actuator control (TAC), throttle position (TP) sensor, or accelerator pedal position (APP) sensor DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. 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

Engine running at operating temperature, raise the engine speed up to 2,500 RPM for 90 seconds and then return to idle. Verify that the engine speed is within 650-750 RPM and the TP sensor value is within 8-13 percent at idle.

If the engine speed or TP sensor are not within the specified range, verify that one of the following conditions is not present:

* Vacuum leaks
* The throttle valve for the correct operation-A throttle valve that does not close correctly sets this DTC.
* Restricted air intake system
* The throttle body for damage and/or tampering
* Incorrect or malfunctioning positive crankcase ventilation (PCV) system-refer to Crankcase Ventilation System Inspection/Diagnosis (Testing and Inspection).
* Excess deposits in the throttle body
* A parasitic load on the engine-For example, a transmission condition, a belt driven accessory condition

• Repair the condition as necessary.

Repair Instructions

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

Throttle Body Assembly Replacement (Service and Repair)