For 1990-2009 cars

### 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

### 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 P0101, P0102, P0103, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0351, P0352, P0353, P0354, P0461, P0462, P0463, P0464, P0496, P0502, P0503, P0806, P0807, P0808, P080A, or P2135 are not set.

• | The barometric pressure (BARO) is greater than 70 kPa.

• | The engine coolant temperature (ECT) is greater than 60°C (140°F).

• | The engine run time is greater than 60 seconds.

• | The ignition voltage is between 11-18 volts.

• | The transmission is not changing gears.

• | The torque converter clutch (TCC) is not changing states.

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

• | The vehicle speed is less than 3 km/h (2 mph).

• | The commanded RPM is steady within 25 RPM.

• | The engine is idling for greater than 10 seconds.

• | The DTCs run when the above conditions are met.

### Conditions for Setting the DTC

#### P0506

The actual engine speed is 91 RPM less than the desired idle speed for 10 seconds.

#### P0507

The actual engine speed is 182 RPM greater than the desired idle speed for 10 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

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

1. Ignition ON, observe the DTC information with a scan tool. Verify there are no other DTCs set.

⇒ | If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Allow the engine to idle within the Conditions for Running the DTC. DTCs P0506 or P0507 should not set.
3. 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 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.

#### P0507

• | 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--Refer to Crankcase Ventilation System Inspection/Diagnosis.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Throttle Body Assembly Replacement

• | Control Module References for ECM replacement, setup, and programming