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 provide an overview of each diagnostic category. |
DTC Descriptors
DTC P0506: Idle Speed LowDTC P0507: Idle Speed High
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
| • | 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, P0446, P0449, P0452, P0453, P0455, P0462, P0463, P0496, P1516, P2101, P2135, P2176 are not set. |
| • | The engine is operating for at least 60 seconds. |
| • | The engine is idling for greater than 10 seconds. |
| • | The engine coolant temperature (ECT) is more than -60°C (-140°F). |
| • | The intake air temperature (IAT) is more than -20°C (-4°F). |
| • | The barometric pressure (BARO) is more than 70 kPa. |
| • | The system voltage is between 9-18 volts. |
| • | The vehicle speed is less than 1.6 km/h (1 mph). |
| • | DTC P0506 and P0507 run 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 200 RPM greater than the desired idle speed.
Action Taken When the DTC Sets
DTCs P0506 and P0507 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0506 and P0507 are Type B 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. |
| • | An intermittent clutch pedal position sensor signal, if equipped, can cause DTC P0506 to set. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Important: The engine must first be running for greater than 60 seconds, then idle at a steady state for an additional 10 seconds before comparing the actual and desired engine idle speed parameters.
- Use a scan tool to compare the desired engine idle speed to the actual engine idle speed.
- 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.
| ⇒ | 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
- Inspect for any condition that can reduce idle speed by increasing engine load.
- Inspect for the following conditions:
| • | Incorrect torque converter clutch (TCC) operation |
| • | Accessories that require additional torque to operate |
| • | Excessive deposits in the throttle body |
| • | Restricted exhaust |
| • | Mechanical conditions that limit engine speed |
| • | Repair any conditions, if necessary. |
| • | Vacuum leaks |
| • | A faulty positive crankcase ventilation (PCV) valve |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
