P0301 / P0302 / P0303 / P0304 fault codes - Misfire detected
P0303: Cylinder 3 misfire detected
The Renault in this example has a 1.6 16V petrol engine rated at 94 hp.
We diagnosed a 2005 Renault Kangoo using an ELM327 adapter and our EOBD Facile software. The vehicle had lost power and its malfunction indicator lamp (MIL) was on. The scan returned one confirmed fault code: P0303. The vehicle's control system had detected a misfire in cylinder 3. Consult the vehicle's workshop manual to identify the correct cylinder. In this example, cylinder 1 is at the flywheel end, on the right of the photo.
Start with the usual basic checks. Have the spark plugs been replaced at the recommended intervals? Are any connectors disconnected or damaged? Is the wiring harness broken or worn? In this case, the vehicle had been maintained and no obvious problem was found.
Confirming the fault
A closer look (Fig. 3-1) reveals that one ignition coil, on cylinder 2, has a green plastic housing. It appears not to be the original part and to have been replaced previously. Some Renault petrol models have had ignition coil reliability issues.
Removing and testing this coil (Fig. 3-2) lets us check that hypothesis. After the coil was removed and replaced, the loss of power appeared to have gone. We could then clear the fault code, carry out a road test and use Mode 7 in our EOBD Facile software to check that the fault had not returned.
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