DTC P0300 Federal Emissions
Circuit Description
The engine control module (ECM) adjusts the fuel delivery to each cylinder in order to minimize crankshaft speed changes. If the ECM identifies a cylinder or cylinders requiring an excessive amount of fuel in order to maintain the correct crankshaft speed, DTC P0300 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0300 Engine Misfire Detected
Conditions for Running the DTC
| • | The engine is running at idle for more than 30 seconds. |
| • | The engine coolant temperature (ECT) is more than 56°C (132°F). |
| • | DTC P0300 runs once per ignition cycle when the above conditions are met. |
| • | DTCs P0301-P0308 must run before P0300 runs. |
Conditions for Setting the DTC
The fuel rate adjustment for more than one cylinder exceeds an acceptable value for more than 30 seconds.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center (DIC), if equipped, may display a message. |
Conditions for Clearing the MIL/DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Use a scan tool in order to clear the DTC. |
Diagnostic Aids
A misfire with no other DTCs will be caused by an engine mechanical or fuel injector problem.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Are any other DTCs set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information |
