No glow-plug continuity

Cause:

• Annular gap between plug shell and heating element constricted or blocked by carbon deposits and the regulating coil remains cold allowing excessive current to reach the heating coil.

Effect:

• Break in heating wire, premature failure

Corrective Action:

• Check injection system
• Check/reset injection timing
• Torque according to specifications
• Replace if necessary

Heating element melted/broken off

Cause:

• Incorrect injection timing
• Carbon buildup on nozzles
• Engine damage (due to valve damage, piston seizure, seized piston rings, etc.)
• Leaking nozzles

Effect:

• Glow plug casting overheats, melts, or breaks

Corrective Action:

• Check injection system (i.e. nozzle-and-holder assembly)
• Check/reset injection timing
• Check for engine damage
• Replace with Bosch quality glow plugs

Ceramic heating element broken

Cause:

• Incorrect injection timing
• incorrect injector spray pattern
• Supply voltage too high (incorrect application)

Effect:

• Ceramic heating element becomes too hot and breaks.

Corrective Action:

• Check engine for oil consumption
• Check control unit function
• Check/reset injection timing
• Replace with Bosch quality glow plugs