Service Information

Spark

DTC P0506 or P0507

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 Descriptors

DTC P0506: Idle Speed Low

DTC P0507: Idle Speed High

The throttle actuator control (TAC) motor is controlled by the engine control module (ECM). The DC motor located in the throttle body drives the throttle blade. In order to decrease idle speed, along with spark and fuel delivery changes the ECM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the ECM commands the throttle plate open allowing more air to pass the throttle plate.

Conditions for Running the DTC

•	DTC P0016, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0351, P0352, P0353, P0354, P0502, P0562, P0563, or P2110 is not set.

•	The engine is idling for greater than 2s.

•	The barometric pressure is greater than 72 kPa (10.4 psi).

•	The intake air temperature is greater than -20°C (-4°F).

•	The engine coolant temperature is greater than -10°C (14°F).

•	The ignition voltage is between 11-16V.

•	The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0506

The actual idle speed is approximately 100 RPM lower than the desired idle speed.

P0507

The actual idle speed is approximately 150 RPM greater than the desired idle speed.

Action Taken When the DTC Sets

DTC P0506 and P0507 are Type E DTCs.

Conditions for Clearing the DTC

DTC P0506 and P0507 are Type E DTCs.

Diagnostic Aids

•	A stalling condition can cause DTC P0506 to set.

•	An intermittent vehicle speed sensor (VSS) signal can cause DTC P0507 to set.

Reference Information

Schematic Reference

Engine Controls Schematics : Siemens ECM - LPG with LCP → Siemens ECM - Gas without FX3 or LCP → Delphi ECM - FX3

Connector End View Reference

Component Connector End Views

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

Note: The engine must first be running for greater than 60s, then idle at a steady state for an additional 10s before comparing the actual and desired engine idle speed parameters.

Using a scan tool compare the Desired Idle Speed parameter to the actual Engine Speed parameter.

•	Actual engine speed should not be less than 100 RPM below desired.

•	Actual engine speed should not be greater than 150 RPM above desired.

Verify that there are no other DTCs set.

⇒	If any other DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

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

Inspect for any condition that can reduce idle speed by increasing engine load.

•	Incorrect torque converter clutch (TCC) operation

•	Accessories that require additional torque to operate

•	More deposits than the customer may desire in the Q38 throttle body

•	Restricted exhaust

•	Mechanical conditions that limit engine speed

⇒	Repair any conditions, if necessary.

Inspect for the following conditions:

•	Vacuum leaks

•	A faulty positive crankcase ventilation valve

⇒	Repair any conditions, if necessary.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for ECM replacement, setup and programming