Troubleshooting Sequence

Does the starter operate


If the starter does not engage or cranks poorly, continue to the section "Cause of Failure — Electrical System". If it cranks the engine firmly, answer the following questions in turn to narrow down the search.

Do the spark plugs produce a spark?


Disconnect the spark plug wire from one of the spark plugs, remove the spark plug, and insert it into the wire boot. Now connect the spark plug to the cylinder block using an auxiliary jumper cable (the auxiliary cable is not shown in the illustration for clarity). Ask an assistant to crank the starter. Do not touch the high-voltage wire or spark plug – dangerous! Is a spark visible? If yes, proceed to the next question. If no, continue to the section "Cause of Failure — Ignition System".

Is fuel being supplied to the injection system?

Disconnect the fuel supply line from the fitting in the engine compartment. Caution: on models with a 5-cylinder engine, a relatively large amount of fuel under high pressure may be discharged. Therefore, when loosening the connection, place a thick rag over the fitting. The fuel supply line can be extended with a hose and its end lowered into a container. Ask an assistant to briefly crank the starter.

If fuel is supplied, the fuel pump must be operating. If not, continue to the section Cause of Failure — Fuel Supply System. If fuel is supplied, the only remaining source of fault is the injection system. Alternatively, the fuel pump may be operating but not producing the required pressure.

(The upper illustration shows the fuel supply system check for a 66 kW engine; the lower illustration shows a 6-cylinder engine).