Checking glow plugs
1. Unscrew the glow plug wires.
2. Connect an ohmmeter in series to each glow plug and check for a short circuit between the glow plug contact and the cylinder block.
3. If the resistance is not zero, the glow plug is defective and should be replaced.
4. Remove the defective glow plug. Screw in a new glow plug (3) and tighten to 20 Nm. Connect the wire (2) and tighten with the nut (1).
Caution! Do not exceed the specified tightening torque, as this may damage the glow rod and cause premature spark plug failure. Be careful not to let oil or fuel come into contact with the spark plug. If the rods are burnt, follow the instructions.
Caution! If no defect is detected, even though the engine is difficult to start, perform a visual inspection of the glow plugs with the glow plugs on. To do this, remove the injection nozzles and observe the glow plugs through the holes as they warm up.
5. If glow plugs are found with burnt heating rods (arrow), it is not enough to simply replace them. In this case, it is also necessary to check the injectors for injection pressure and tightness.
6. Burning glow plug rods are often caused by faulty injectors. Such damage should not be attributed to an internal or external defect of the glow plug.
Checking the glow plug relay
1. Remove the glow plug relay connector.
2. Connect the relay to the battery with two wires. Connect an ohmmeter and check if the terminals are shorted.
3. If the terminals are not shorted, the relay should be replaced.