LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 2006 >> Allure CX >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.8L - DTC P0451 To DTC P2120 >> DTC P0506 >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

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

  1. 2:  This test determines whether the engine can achieve the commanded RPM. If the engine does not reach the commanded RPM, the test determines whether the RPM is too high or too low.
DTC P0506

Step Action Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views and Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
  1. Start the engine.
  2. Ensure the engine is at operating temperature.
  3. Command the engine speed to 1,500 RPM, then to 500 RPM and back to 1,500 RPM with a scan tool.
  4. Exit the RPM control function.
Does the engine speed correspond, within 100 RPM, with each command?
Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3 Inspect for any condition that can reduce idle speed by increasing engine load. The following examples are possible conditions:
  • Incorrect torque converter clutch (TCC) operation
  • Accessories that require additional torque to operate
  • Restricted exhaust
  • Mechanical conditions that limit engine speed

Did you complete the action?
Go to Step 4  -
4
  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 5 
5
IMPORTANT: Be aware that repairing 1 individual condition may correct more than 1 DTC.
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