Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Cadillac >> 2008 >> DTS 4.6 9 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 4.6L - DTC P0340 To DTC P2138 >> DTC P0506 or P0507 >> Circuit System Testing

Circuit System Testing

  1. Inspect for any condition that can reduce idle speed by increasing engine load.
    • Incorrect torque converter clutch (TCC) operation
    • Accessories that require additional torque to operate
    • Excessive deposits in the throttle body-Refer to Throttle Body Inspection and Cleaning .
    • Restricted exhaust-Refer to Restricted Exhaust .
    • Mechanical conditions that limit engine speed
  2. Inspect for any condition that can increase idle speed.
    • Vacuum leaks
    • Unmetered air entering the engine, after the mass air flow
    • A faulty positive crankcase ventilation (PCV) valve
scientia non olet · About Mike's Workshop Manuals