GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Generic 🢒 2008 🢒 Unit Repair 🢒 Engine 🢒 Engine Controls and Fuel - Ram-Jet 🢒 DTC P0506 or P0507

Diagnostic Instructions
    • Perform the Powertrain On Board Diagnostic (OBD) System Check 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

Circuit/System Description

The throttle actuator control (TAC) motor is a DC motor that is part of the throttle body assembly. The TAC motor drives the throttle valve. The engine control module (ECM) controls the TAC motor based on throttle position sensor input. The idle speed is controlled by the ECM based on various inputs. The ECM commands the TAC motor to open or close the throttle valve in order to maintain the desired idle speed.

Conditions for Running the DTC
    • DTCs P0068, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0122, P0123, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0335, P0336, P0641, P0651, P1516, P2101, P2135 are not set.
    • The engine run time is greater than 2 seconds.
    • The intake air temperature (IAT) is greater than -40°C (-40°F).
    • The engine coolant temperature (ECT) is greater than -40°C (+40°F).
    • The engine is idling.
    • The barometric pressure (BARO) is greater than 65 kPa.
    • The ignition voltage is between 9-18 volts.
    • The DTCs run when the above conditions are met for 3 seconds.

Conditions for Setting the DTC

P0506

The actual engine speed is less than the desired idle speed by at least 150 RPM for 15 seconds.

P0507

The actual engine speed is greater than the desired idle speed by at least 100 RPM for 15 seconds.

Action Taken When the DTC Sets

DTCs P0506, and P0507 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0506, and P0507 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Engine Control Module Scan Tool Information

Circuit/System Verification
  1. Allow the engine to idle within the conditions for running the DTCs for 1 minute. DTCs P0506 or P0507 should not set.
  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

P0506

    • Inspect the engine for vacuum leaks.
    • Inspect the throttle valve for the correct operation. A throttle valve that does not close correctly sets this DTC.
    • Verify the correct operation of the crankcase ventilation system. Inspect for the following conditions:
       - The routing of the positive crankcase ventilation (PCV) system
       - Vacuum leaks in the PCV system

P0507

    • Inspect for excess deposits in the throttle body.
    • Inspect for a parasitic load on the engine--For example, a transmission condition, a belt driven accessory condition.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Throttle Body Assembly Replacement
    •  Engine Control Module Replacement for ECM replacement, setup, and programming