P0303

DTC P0301, P0302, P0303 or P0304 Cylinder 1, 2, 3 or 4 Misfire Detected

Circuit Description

The ECM monitors changes in crankshaft speed using inputs from the crankshaft position (CKP) sensor. The ECM adjusts the fuel delivery amount 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 it is considered misfire and DTC P0301 P0302 P0303 or P0304 will set depending upon which cylinder failed.

Condition for Running the DTC

^ DTCs P0016 P0089 P0091 P0092 P0093 P0112 P0113 P0116 P0117 P0118 P0192 P0193 P0201 - P0204 P0261 P0264 P0267 P0270 P0335 P0336 P0500 P0506 P0507 P0602 P0642 P0643 P0652 P0653 P1093 P1125 P2146 - P2151 P1293 P2227 P2228 P2229 and P268A are not set.
^ The battery voltage is between 10 to 16 volts.
^ The engine speed is between 500 to 1050 RPM.
^ The desired idle speed does not vary more than 100 RPM.
^ The vehicle speed is less than 2 MPH (3 km/h).
^ The engine coolant temperature is more than 19°F (-7°C).

Condition for Setting the DTC

^ The ECM detects that the fuel injection balancing rate is more than 30 mm3 for longer than 70 seconds.

Action Taken When the DTC Sets

^ The ECM illuminates the MIL on the second consecutive driving cycle when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type B.
^ The ECM inhibits EGR control.
^ The ECM inhibits DPF regeneration control.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type B.

Diagnostic Aids

^ An engine mechanical or fuel injector problem will cause this DTC(s) to set.
^ Use a scan tool to observe the Balancing Rate for each cylinder at idle. A cylinder that is excessively large or small balancing rate may indicate incorrect fuel injector flow rate faulty fuel injector(s) and weak or slightly seized cylinder.

Notice: Each DTC agrees with engine cylinder order.

^ P0301: Cylinder #1
^ P0302: Cylinder #2
^ P0303: Cylinder #3
^ P0304: Cylinder *4

Circuit/System Testing DTC P0301, P0302, P0303 or P0304