DTC P0506 or P0507. Buick LaCrosse 2006

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2006 🢒 LaCrosse 🢒 DTC 🢒 DTC P0506 or P0507

Circuit 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.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

•	DTC P0506 Idle Speed Low

•	DTC P0507 Idle Speed High

Conditions for Running the DTC

•	Before the ECM can report DTC P0506 or P0507 failed, transmission DTCs P0723 and P0723 must run and pass.

•	DTCs P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, P0722, and P0723 are not set.

•	The engine is operating.

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

•	The intake air temperature (IAT) is more than -10.5°C (+13°F).

•	The volumetric efficiency is less than 35 percent, DTC P0506 only.

•	The evaporative emission (EVAP) canister purge valve is OFF.

•	A vehicle speed was detected prior to the diagnostic running.

•	The vehicle speed is 0 km/h (0 mph).

•	DTC P0506 and P0507 run continuously once the above conditions are met for more than 10 seconds.

Conditions for Setting DTC P0506

The actual engine speed is less than the desired idle speed by at least 100 RPM for 4 seconds.

Conditions for Setting DTC P0507

•	The actual engine speed is more than the desired idle speed by at least 200 RPM for 4 seconds.

•	The ECM detects 3 fuel cut-offs due to an engine over speed condition while the engine is idling.

Action Taken When the DTC Sets

•	The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

•

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

•	The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

•	A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

•	A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

•	Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

The following table illustrates the ECM connector locations:

ECM Connector Location
C2	C1
Front of Vehicle

•	Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.

•	For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

If any of the listed DTCs are present, correct the condition before returning to this table.

This test determines whether the engine can achieve the commanded RPM, and if not, whether the engine speed is too high or too low.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Are any throttle actuator control (TAC), throttle position (TP) sensor, or accelerator pedal position (APP) sensor DTCs set?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

Start the engine.
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.

Is the actual engine speed within the specified value of the commanded engine speed with each command?

100 RPM

Go to Step 4

Go to Step 5

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
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.

Did the DTC fail this ignition?

Go to Step 5

Go to Intermittent Conditions

Is the engine speed more than the specified value above the desired RPM?

100 RPM

Go to Step 6

Go to Step 7

Inspect or test for the following conditions:

•	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.

•	Inspect the crankcase ventilation system for the correct operation. Inspect for the following conditions:

-	Inspect that the correct positive crankcase ventilation (PCV) valve is used.

-	Inspect the routing of the PCV system.

-	Inspect for vacuum leaks in the PCV system.

Repair the condition as necessary.

Did you complete the repair?

Go to Step 8

Inspect for the following conditions:

•	Inspect for excess deposits in the throttle body.

•	Insect for a parasitic load on the engine, for example, a transmission condition or a belt driven accessory condition.

Repair the condition as necessary.

Did you complete the repair?

Go to Step 8

Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
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.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 9

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK