GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Avalanche - 4WD 🢒 Engine 🢒 Engine Controls - 4.8L, 5.3L, and 6.0L 🢒 DTC P0506

Circuit Description

The throttle actuator control (TAC) system uses various inputs from the powertrain control module (PCM). This system uses the inputs in order to control the idle speed through serial data circuits to the TAC module. The DC motor, which is located in the throttle body, activates the throttle plate. In order to decrease idle speed, the TAC module commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase the idle speed, the TAC module commands the throttle plate open allowing more air flow. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC will set.

Conditions for Running the DTC
    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0171, P0172, P0174, P0175, P0200, P0220, P0300, P0442, P0443, P0452, P0453, P0455, P0496, P0500, P0502, P0503, P2135 are not set.
    • The engine is running for greater than 60 seconds.
    • The engine coolant temperature (ECT) is greater than 60°C (140°F).
    • The intake air temperature (IAT) is greater than -10°C (+14°F).
    • The barometric pressure (BARO) is greater than 65 kPa.
    • The system voltage is between 9-18 volts.
    • The vehicle speed is less than 1.7 km/h (1 mph).
    • The accelerator pedal position (APP) sensor is at 0 percent.

Conditions for Setting the DTC
    • The actual idle speed is 100 RPM less than the desired idle speed.
    • All of the above conditions are present for 5 seconds.

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 3 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.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This test determines if the engine can achieve the commanded RPM.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Set the park brake, and block the drive wheels.
  2. Start the engine.
  3. Turn OFF all accessories.
  4. With the engine speed control function of the scan tool, command the engine RPM to 1,500 RPM, to 500 RPM, and back to 1,500 RPM.
  5. Exit the engine speed control function.

Did the engine speed stay within 100 RPM of the commanded RPM during the above test?

Go to Step 3

Go to Step 4

3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 4

Go to Intermittent Conditions

4

Inspect for the following conditions:

    • Deposits in the throttle body
    • Objects which are blocking the air intake system
    • Energy-draining load on the engine, such as transmission conditions

Did you complete the repair?

Go to Step 5

--

5
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 6

6

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK