DIESEL
A6
CIRCUIT OPERATION
4
Main Relay
Located in the ECM (Z132) box, this relay supplies
the power feed to the ECM (Z132). It is controlled via
the Ignition Switch (X274) in position II.
Glow Plug Relay (Z135)
The Glow Plug Relay (Z135) takes a feed directly
from the battery and, on initialisation via the ECM
(Z132), supplies current to each of the six glow plugs
(one per cylinder) to aid cold starting. The glow time
is controlled via the ECM (Z132) which also monitors
the relay and illuminates the glow plug indicator lamp
for the duration of the glow time. This relay is
relatively large and is located with the main relay
next to the ECM (Z132).
Starter Motor Relay
This relay is also ignition key controlled, activated
with the key in the ignition III position only. Releasing
the key after cranking cuts supply to the relay and
switches off the starter motor.
Fuel Pump Relay
The fuel pump relay is pulled in when the starter
motor is activated, the earth path provided by the
alternator output. When the engine is running, the
starter motor is deactivated, supplying an earth path
while the generator supplies a feed i.e. a polarity
reversal.
ECM (Z132)
If the ECM (Z132) itself is not working, the entire
engine management system will cease to operate,
i.e. no fuel, tacho reading, etc.