Diagnostic Instructions
DTC Descriptors
DTC P0506: Idle Speed Low
DTC P0507: Idle Speed High
DTC P050A: Cold Start Idle Air Control (IAC) System Performance
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. If the ECM detects the actual idle speed and the desired idle speed are not within a predetermined
amount, this DTC sets.
Conditions for Running the DTC
P0506 and P0507
| • | DTC P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, or P0700 is not set. |
| • | The engine is operating for greater than 4 seconds. |
| • | The vehicle speed is 0 km/h (0 mph) and accelerator pedal position (APP) input at 0 percent. |
| • | The cold start idle speed control is not active. |
| • | The evaporative emission (EVAP) canister purge valve command less than 40 percent. |
| • | The EVAP intrusive leak test is not enabled. |
| • | The intake air temperature (IAT) is warmer than -11°C (+13°F). |
| • | The engine coolant temperature (ECT) is warmer than -11°C (+13°F). |
| • | A vehicle speed was detected prior to the diagnostic running. |
| • | The engine load is less than 100 percent, P0506 only. |
| • | DTC P0506 and P0507 run continuously once the above conditions are met for greater than 10 seconds. |
P050A
| • | DTC P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, or P0700 is not set. |
| • | The cold start idle speed control is enabled. |
| • | The vehicle speed is 0 km/h (0 mph) and accelerator pedal position (APP) input at 0 percent. |
| • | The ECT at start up is colder than 65°C (149°F). |
| • | DTC P050A runs once an ignition cycle when the conditions above have been met for 7 seconds. |
Conditions for Setting the DTC
P0506
The actual engine speed is less than the desired idle speed by at least 100 RPM for greater than 4 seconds or for a cumulative of 30 seconds.
P0507
| • | The actual engine speed is greater than the desired idle speed by at least 200 RPM for greater than 4 seconds or for a cumulative of 30 seconds. |
| • | The ECM detects 3 fuel cut-offs due to an engine over speed condition while the vehicle speed is zero. |
P050A
The actual engine speed is 100 RPM less or 200 RPM greater than the desired idle speed, for greater than 4 seconds or a cumulative of 30 seconds, during a cold start.
Action Taken When the DTC Sets
DTCs P0506, P0507, and P050A are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0506, P0507, and P050A are Type B DTCs.
Diagnostic Aids
Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
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
- Observe the DTC information with a scan tool.
| ⇒ | If there are any throttle actuator control (TAC), throttle position (TP) sensor, accelerator pedal position (APP) sensor, or fuel rail pressure (FRP) regulator DTCs set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle. |
- Operate the engine within the conditions for running the DTCs for 1 minute. DTC P0506, P0507, or P050A should not set.
- 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
Engine operating, command the engine speed up to 1,400 RPM, down to 600 RPM, up to 1,400 RPM, and then exit using the scan tool. The engine speed should steadily increase and decrease as commanded.
| ⇒ | If the idle does not increase or decrease steadily, verify that one of the following conditions is not present: |
| • | The throttle valve for the correct operation--A throttle valve that does not close correctly sets this DTC. |
| • | Restricted air intake system |
| • | The throttle body for damage and/or tampering |
| • | Incorrect or malfunctioning PCV system |
| • | Excess deposits in the throttle body |
| • | A parasitic load on the engine--For example, a transmission condition, a belt driven accessory condition |
| ⇒ | Repair the condition as necessary. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
