DTC P0300-A: MULTIPLE CYLINDER MISFIRE Chrysler LHS II

Note. For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.

1. Using scan tool, read Diagnostic Trouble Codes (DTCs). If scan tool display MISFIRE GOOD TRIP is equal to zero, go to next step. If scan tool display MISFIRE GOOD TRIP is not equal to zero, go to step 7 .
2. Condition to set trouble code is not present at this time. Using scan tool, read FREEZE FRAME data and SIMILAR CONDITIONS WINDOW. Attempt to operate vehicle in similar conditions. When in SIMILAR CONDITIONS WINDOW, go to WHICH CYLINDER IS MISFIRING monitor. If scan tool is counting misfires at this time, go to next step. If scan tool is not counting misfires at this time, go to step 7 .
3. Using FREEZE FRAME data, examine adaptive fuel percentages. If adaptive fuel percentages are not more than plus or minus 15 percent, go to next step. If adaptive fuel percentages are more than plus or minus 15 percent, problem is fuel delivery or quality. Perform appropriate fuel system tests. Repair as necessary. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S06971814902000030800000) .
4. Using FREEZE FRAME data, examine load value percentage and operating temperature. If load value is 40 percent or less and operating temperature is not normal, go to next step. If load value is more than 40 percent and operating temperature is normal, inspect secondary ignition components, and check cylinder compression. Repair as necessary. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S06971814902000030800000) .
5. Using FREEZE FRAME data, examine engine RPM and operating temperature. If engine speed is more than 3000 RPM and operating temperature is normal, check camshaft and crankshaft sensors using a lab scope. Check engine valve timing. Check engine vacuum. Repair as necessary. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S06971814902000030800000) . If engine speed is not more than 3000 RPM and operating temperature is not normal, go to next step.
6. Possible causes are: secondary ignition failure, fuel pump or filter, fuel injector harness connections, ignition coil circuit, spark plug, engine mechanical problem, contaminated fuel, PCM power or grounds, fuel injectors, restricted exhaust, restricted intake, Powertrain Control Module (PCM) failure, EVAP system, Exhaust Gas Recirculation (EGR) system or damaged trigger wheel. Repair as necessary. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S06971814902000030800000) .
7. At this time condition does not exist. An intermittent problem may have been caused by moisture in secondary ignition. Using scan tool, read FREEZE FRAME data and SIMILAR CONDITIONS WINDOW. Attempt to operate vehicle in similar conditions. Pay particular attention to code set conditions: engine RPM, coolant temperature, engine load and manifold vacuum. If a misfire reoccurs, return to step 1 . If a misfire does not reoccur, operate vehicle for one misfire good trip. Erase DTC. Test is complete. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S06971814902000030800000) .