DTC P0300: Random Misfire Detected
- Connect TECH 2 scan tool to Data Link Connector (DLC). Turn ignition on. Obtain a FREEZE FRAME readout for DTC P0300 and record values for ENGINE RPM, AIRMASS/COMBUSTION and COOLANT TEMPERATURE. Check scan tool for any stored DTCs. If DTCs P1300, P1301-P1304, P1390 or P1391-P1394 are present, go to appropriate test procedure for diagnostics. If none are present, go to next step.
- If DTCs P0171, P0172, P1171, P1172, P1181, P1182, P1641 or P1676 are present, go to appropriate test procedure for diagnostics. If none are present, go to next step.
- Check all hoses and intake system components between turbocharger and throttle body. Inspect vacuum hose between intake manifold and fuel pressure regulator. Check scan tool COOLANT TEMPERATURE value and compare to actual engine temperature. Repair any leaks or electrical circuit problems found. Go to next step.
- Check engine compression and replace spark plugs. See SPARK PLUGS
under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. If any mechanical problems are found, repair as necessary and go to step 6. If engine compression readings are okay, go to next step.WARNING: Ignition discharge module (IDM) can discharge in excess of 40,000 volts. Ensure that spark plugs are properly grounded, and keep adequate distance from IDM while conducting following test.
- Test ignition discharge module (IDM) operation. See IGNITION DISCHARGE MODULE (IDM) under MODULES, RELAYS & SOLENOIDS in appropriate SYSTEM & COMPONENT TESTING article. If any ignition coil does not operate as specified, replace IDM and go to next step. If all coils operate as specified, go to DTC P1171-P1172: SHORT TERM FUEL TRIM LEAN OR RICH MIXTURE .
- Use scan tool to select ACTIVATE: RESET MISFIRE AND KNOCK COUNTERS. Test drive vehicle while duplicating previous freeze frame values noted for ENGINE SPEED, AIR MASS/COMBUSTION and COOLANT TEMPERATURE. If any misfire/knock counters are incrementing continuously, problem is still present. Repeat diagnostic procedure. If no counters are incrementing continuously, clear all system DTCs.