GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Caprice WM 🢒 DTC 🢒 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 Control System RPM Lower Than Expected

DTC P0507: Idle Control System RPM Higher Than Expected

Circuit/System Description

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 P0506 and P0507
    • DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0221, P0222, P0223, P0230, P0300, P0336, P0442, P0463, P1516, P2101, P2135, P2176 are not set.
    • The engine is operating for at least 60 seconds.
    • The engine coolant temperature (ECT) is more than +60°C (+140°F).
    • The intake air temperature (IAT) is more than -10°C (-14°F).
    • The barometric pressure (BARO) is more than 65 kPa.
    • The system voltage is between 9-18 volts.
    • DTC P0506 and P0507 run continuously once 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.
    •  The above condition is present for 5 seconds.

Conditions for Setting the DTC P0507
    • The actual idle speed is approximately 200 RPM greater than the desired idle speed.
    •  The above condition is present for 12 seconds.

Action Taken when the DTC Sets

DTCs P0506 or P0507 are type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0506 or P0507 are type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

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

Scan Tool Reference

Control Module References

Circuit/System Verification
    • Using a scan tool compare the desired engine idle speed to the actual engine idle speed.
    • Actual engine idle speed should be no greater than 100 RPM below desired.
    • Actual engine idle speed should be no greater than 200 RPM above desired.

Circuit/System Testing
  1. If there are any other DTCs set, diagnose those first.
  2. Inspect for any condition that can reduce idle speed by increasing engine load.
    3. • Incorrect torque converter clutch (TCC) operation.
    • Accessories that require additional torque/load to operate.
    • Excessive deposits in the throttle body.
    • Restricted exhaust.
    • Mechanical conditions that limit engine speed.
  3. Inspect for the following conditions:
    4. • Vacuum leaks.
    • A faulty positive crankcase ventilation (PCV) valve.

Repair Instructions

Perform the Control Module References after completing the diagnostic procedure.