P0303

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The scan tool indicates Diagnostic Trouble Code (DTC) P0303: Cylinder 3 misfire detected.


Advanced Diagnostics















Description
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensor which is attached to the crankshaft.
If misfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and DTC P0301, P0302, P0303 or P0304 will be stored. Then, after the misfire has ceased, the MIL will come on.
If misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC P0301, P0302, P0303 or P0304 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as a misfire DTC, troubleshoot those DTCs first, then recheck for the misfire DTC.

P0106*4, P0107, P0108, P1 128*3, *5, P1 129*3, *5: MAP sensor
P0131, P0132: HO2S
P0171, P0172: Fuel supply system
P0335, P0336: CKF sensor
P0401, P1491, P1498: EGR system
P0441: EVAP system Insufficient purge flow*6
P1359, P1361, P1362: TDC sensor
P1381, P1382: CYP sensor

*4: '96 models
*6: '96 D16Y5 engine, '96 D16Y7 engine, '96 D16Y8 engine (sedan), '97 D16Y5 engine, '97 D16Y7 engine (coupe: KA, KC models, sedan KA, KC, KL (DX) models, hatchback: all models), '97 D16Y8 engine (sedan: KA, KC models)

Possible Cause
- Fuel injector clogging, fuel leakage, air leakage
- Fuel injector circuit open or shorted
- Spark plug carbon deposits, fouling, malfunction
- Ignition wires open, leaking
- Distributor malfunction
- Compression low
- Valve clearance out of spec
- VTEC system malfunction (D16Y5, D16Y8, B16A2 engine)
- HO2S
- HO2S circuit