TD5 Defender Engine Management System: Glow Plugs - Page 332
ENGINE MANAGEMENT SYSTEM
25
DESCRIPTION AND OPERATION
Input / Output
The glow plugs receive a feed from the glow plug relay (C0215-3) on a yellow/black then individual black wires.
The ECM provides the earth path for the glow plug relay (C0151-6), working in tandem with the Alarm ECU. The
supply voltage heats the coils to approximately 1000
°
C (1832
°
F). The glow plug circuit is wired in parallel, the
body of each glow plug is screwed directly into the engine block which provides each glow plug with an earth path.
The glow plugs can fail in one or more of the following ways:
•
Heater coil open circuit.
•
Control coil open circuit.
•
Poor earth quality.
•
Short circuit to vehicle supply.
•
Short circuit to vehicle earth.
•
Harness fault.
•
Relay windings open circuit.
•
Incorrect relay fitted.
In the event of a glow plug failure, any of the following symptoms may be observed:
•
Difficult starting.
•
Excessive smoke emissions after engine start.
