P0300-MISFIRE DETECTED

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the engine running.
Set Condition:
The ECM detects multiple misfires from one or more cylinders.

Possible Causes

ENGINE COMPRESSION

FUEL INJECTOR QUANTITY

FUEL SUPPLY CONTAMINATION

INJECTOR LEAKAGE

INTERMITTENT CONDITION

Diagnostic Test

1.CHECK FOR ACTIVE DTC

NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

Did this DTC set again?

Yes

Go To2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2.FUEL CONTAMINATION

Is the fuel contaminated?

Yes

Refer to the Service Information to remove and replace fuel throughout the fuel system.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Go To3

3.ENGINE COMPRESSION

Is the cylinder compression within specification for all cylinders?

Yes

Go To4

Repair as necessary in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

4.FUEL INJECTOR QUANTITY

Is the Injector Quantity within specification for all cylinders?

Yes

Go To5

Repair or replace as necessary in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

5.FUEL INJECTOR LEAKAGE

Were any problems found?

Yes

Repair or replace as necessary in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Test Complete.