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 or P0507
| • | Before the ECM can report DTC P0506 or P0507 failed, DTC P0700 must run and pass. |
| • | DTCs P0111, P0112, P0113, P0117, P0118, P0119, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, and P0700 are not set. |
| • | The engine is operating. |
| • | The engine coolant temperature (ECT) is greater than -10°C (14°F). |
| • | The intake air temperature (IAT) is greater than -10°C (14°F). |
| • | The volumetric efficiency is less than 35 percent, DTC P0506 only. |
| • | The evaporative emission (EVAP) canister purge valve is OFF. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | DTC P0506 and P0507 run continuously once the above conditions are met for greater than 10 seconds. |
P050A
| • | DTCs P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, and P0700 are not set. |
| • | The engine is operating. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | The volumetric efficiency is less than 35 percent. |
| • | The ECT is -10 to +40°C (+14 to +104°F) at cold start. |
| • | DTC P050A runs once an ignition cycle when the conditions above have been met for 5 seconds. |
Conditions for Setting the DTC
P0506
The actual engine speed is less than the desired idle speed by at least 100 RPM for 4 seconds or for a cumulative of 50 seconds.
P0507
| • | The actual engine speed is greater than the desired idle speed by at least 200 RPM for 4 seconds or for a cumulative of 50 seconds. |
| • | The ECM detects 3 fuel cut-offs due to an engine over speed condition while the engine is idling. |
P050A
The actual engine speed is more or less than the desired idle speed by at least 100 RPM for 4 seconds or a cumulative of 50 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
The following table illustrates the ECM connector locations:
ECM Connector Location
|
X2
| X1
|
Front of Vehicle
|
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
- Ignition ON, observe the scan tool DTC information. Verify there are no throttle actuator control (TAC), throttle position (TP) sensor, or accelerator pedal position (APP) sensor DTCs 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 are captured in the Freeze Frame/Failure Records Data List.
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 with a 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.
