2. On the 4-cylinder M43TU engine, check the condition of the high-voltage wires as follows.
Note: On N42 engines it is not possible to test the high voltage wires.
- a) Make sure the wires are marked according to the cylinder numbers. Pull the tip of the first wire off the spark plug.
- b) Inspect the inside of the wire tip for corrosion, which appears as a white, loose powder.
- c) Put the tip back on the spark plug. Check if it is tightly seated on the spark plug. If not, pull the tip off the spark plug again and squeeze the metal contact inside the tip with pliers.
- d) Wipe the entire length of the wire with a clean rag to remove dirt and grease. Inspect the wire for cracks, swelling, and other damage. Do not bend the wire too sharply or try to stretch it - the conductor inside the wire may break.
- d) Put the wire back on the spark plug.
- e) Check the remaining high-voltage wires in the same way.
3. Check that the accelerator cable is adjusted correctly as described in Chapter 4A.
4. If the engine runs very rough, check the compression as described in Chapter 2.
5. If these checks do not reveal the cause of the malfunction, contact a service station or dealer for an instrumental check. If the malfunction really exists, then the ECU self-diagnosis system has detected this malfunction and entered its code into its memory. The malfunction code can be retrieved from the ECU memory using a special device - a code reader, which is connected to the diagnostic connector of your car. The code reader allows you to find the location of the malfunction easily and quickly, without resorting to the tedious procedure of sequentially checking systems and wires (which is also dangerous for the BEU).