GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Detonation/Spark Knock

Checks

Action

DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

Preliminary Checks
    • Refer to Symptoms - Engine Controls .
    • Search for service bulletins.

Fuel System
    • Inspect for low fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect items that can cause an engine to run lean--Short term FT significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Ignition System
    • Inspect the spark plugs for proper heat range and reach. Refer to Spark Plug Replacement .
    • Inspect the knock sensor (KS) system for no retard timing.

Engine Cooling System

Inspect for obvious overheating problems:

    • Low engine coolant--Refer to Loss of Coolant in Engine Cooling.
    • Restricted air flow to radiator, or restricted water flow through radiator
    • Inoperative fan clutch
    • Correct coolant solution should be a 50/50 mix of DEX-COOL or equivalent antifreeze coolant and water.

Engine Mechanical
    • Inspect for excessive oil in combustion chamber and leaking valve seals. Refer to Oil Leak Diagnosis in Engine Mechanical 2.2L (L43).
    • Inspect for low cylinder compression.
    • Inspect combustion chambers for excessive carbon buildup. Use ONLY an approved cleaner that is compatible with ethanol fuel in the fuel tank.
    • Inspect the following components for incorrect basic engine parts:
       - Camshaft
       - Cylinder heads
       - Pistons, etc.
    • Refer to A Symptoms - Engine Mechanical in Engine Mechanical 2.2L (L43).

Additional Checks
  1. Inspect the park/neutral position (PNP) switch input with the vehicle in drive and the gear selector in drive or overdrive.
  2. Inspect the torque converter clutch (TCC) operation. The TCC applying too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis in Automatic Transmission.
  3. If scan tool readings are normal and there are no engine mechanical malfunctions, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87 and re-evaluate vehicle performance.