P0506

****Some values in these diagnostic procedures are incorrect, refer to the following 2 tables for updated values or to TSB - 03-36-024 for updated values****













DTC P0506 Idle RPM Lower Than Expected

DESCRIPTION
The Idle Speed Control (ISC) actuator has two coils that are driven by separate ECM driver stages. Depending on the pulse duty factor, the equilibrium of the magnetic forces of the two coils will result in different directions for the magnetic forces of the two coils which will result in different p0sitions for the actuator. In parallel to the throttle valve, a bypass hose line is arranged where the ISC actuator is inserted.

FAILURE CONDITIONS
The ECM will set P0506 or P0507 and the MIL will turn on if for 15 seconds the ISC actuator driver circuit values and engine idle speed are not in agreement with values stored in the ECM during two driving cycles when the following conditions are met:
1. The ISC actuator passes idle air at a rate above 4.1 g/s. [for P0506] or 1.7 g/s [for P0507).
2. Engine speed deviation is below 200 RPM.
3. Vehicle speed is zero.
4. Engine coolant temperature is above 167 °F (75 °C).

This code indicates the idle speed control actuator and the engine do not agree with the ECM on the idle speed value.

Circuit Diagram:

Test Procedure Part 1:

Test Procedure Part 2: