GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 VUE - FWD 🢒 Engine 🢒 Engine Controls - 3.5L (L66) 🢒 DTC P0506

Description

The DTC P0506 Idle Speed Low diagnostic monitors the engine speed. The powertrain control module (PCM) controls the throttle actuator control (TAC) motor in order to regulate the air flow through the throttle body. The amount of air flowing through the throttle body determines the engine speed. If there is a malfunction in the TAC system or other engine control system, DTC P0506 can set.

DTC Descriptor

This diagnostic procedure supports the following DTC.

DTC P0506 Idle Speed Low

Conditions for Running the DTC
    • DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0172, P0174, P0175, P0222, P0223, P0300-P0306, P0401, P0404, P0507, P1128, P1129, P2100, P2101, P2108, P2122, P2123, P2127, P2128, P2135, P2138, P2176, P2227, P2228, P2229, P2413, and U0107 are not set.
    • Battery voltage is at least 10.5 volts.
    • Intake air temperature (IAT) is at least 69°C (156°F).
    • Engine coolant temperature (ECT) is at least 0°C (32°F).
    • The engine has been running at least 15 seconds.
    • Engine is running in Closed Loop at idle
    • The throttle valve is fully closed
    • The vehicle is in PARK with all engine accessories turned OFF
    • DTC P0506 runs once per drive cycle when the above conditions are met.

Conditions for Setting the DTC
    • The actual engine speed is 100 RPM less than the desired engine speed.
    • The above condition exists for more than 20 seconds.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.
    • The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

Conditions for Clearing the MIL/DTC
    • The MIL turns OFF after 3 consecutively passing trips without a fault present.
    • A history DTC clears after 40 consecutive warm-up cycles without a fault.
    • Perform the scan tool Clear DTC Information function.

Diagnostic Aids

An incorrect TP learned value can cause a DTC P0506 to set. Reset the TP learned value. Refer to Scan Tool Output Controls .

Any malfunction that can cause a low idle condition can cause a DTC P0506 to set.

For an intermittent malfunction refer to Intermittent Conditions .

Test Description

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

  1. The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

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

Go to Step 3

3
  1. Start the engine.
  2. 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

4

  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 5

Go to Intermittent Conditions

5
  1. Inspect for the following conditions:
    2. • Inspect for excess deposits in the throttle body
    • Insect for a parasitic load on the engine -- For example, a transmission condition, a belt driven accessory condition
  2. Repair the condition as necessary.

Did you complete the repair?

--

Go to Step 6

--

6
  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 7

Go to Step 2

7

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