Volvo 819 E - Page 62

Group 28 Ignition systems
Design and function - System descriptions
L- +.--_+- __ -="---\.
I- -------l "
,
•
• b ,.B ,
198
84
86
,
1.7121
•
REX-I
Control un it connections
1. Transmits signals to diagnosti c un it (482) when fault tracing. Signals are transm i ned by diagnosti c un it when ap-
propriate diagnost ic funct ions are selected.
2.
Receives engine temperature signal from temperature sensor ( 84 ) for tim ing compensation . if required. Contro l
unit supplies one of NTC resistors in sensor with constant voltage and measures resulting voltage level in-
ternally .
3.
Grounds connection when certain types of fault are present in system. Ground i ng closes circ uit to combined in -
strument, illuminating 'Check engine' warning lamp (1217) .
4. Spare.
5. Receives supply from battery (1) for self- diagnostic program memory.
6. Receives supply from battery (1) across ignition switch ( 2) terminal 15 .
7. Receives signal
from throttle switch (198) when throttle is fully closed. Control unit respond by selecting timing
curve which is speed- dependent only .
8. Receives
engine load si gnal from Regina control un it (473) for c omputat i on of timing .
10 . Receives engine speed and crankshaft pos i tion signals from spee d/ position pick- up (413) for computat i on of tim -
ing .
11 . Connection for screen of lead from speed/position pick - up (413 ).
12 . Grounds screen of lead from knock sensor (218 ).
13 . Receives signal from kn oc k sensor (218) for retardation of timi ng in cyli nder affected by knock.
14 . Spare.
15 . Spare.
6'