Pontiac Fiero 1988 Service Manual page 659

SE3-CMQ DRIVABIUTY AND EMISSIONS - FUEL INJECTION (PORT)
IGN
901 GRY/RED - J
A
4
IGN
12V
GAGES
20A
EGRCONTROL
"SES" LIGHT
4 1 9 BRW/WHt
PNK/BLK
3RD GEAR
OIL PRESSURE
SWITCH
BRAKE
SWITCH
ALDL CONNECTOR
[TJ
IGN 1
TCC SOLENOID
GAGE
SHIFT
LIGHT
M/T ONLY
o — 422 TAN/BLK
458 TAN/BLK
TO A/C
COMPRESSOR
TO A/C
POWER RELAY
0>SEE CHART C-1Q
459 DK BLU
~i
C2
67 LT BLU - I B8
AC
CONTROL
SWITCH
PRESSURE
CYCLING
SWITCH
ECM
EGR CONTROL
SERVICE ENGINE
S O O N " LAMP
TRANSAXLE
CONVERTER
CLUTCH
O i
SHIFT LIGHT
M/T
A/C CLUTCH
RELAY
CONTROL
A/C REQUEST
SIGNAL
6-15-87
8S 4590-6E
7-1-87
EGIVS QDR CHECK
2.8L " P " SERIES (PORT)
ECM Q u a d D r i v e r (QDR) Check
The ECM used an integrated circuit (IC) called a
quad driver (QDR) in place of separate transistors to
turn " O N " or "OFF" different circuits controlled by
the ECM. Each QDR has four separate outputs that
can independently turn " O N " or "OFF" four different
circuits.
ECM service part number 1227170, used with this
engine, does not have fault protection, therefore, a
single faulty circuit many times causes all four QDR
outputs to be inoperative or " O N " all the time. A
failed QDR usually results in either a shorted or open
ECM output. Because of the increased current flow,
two QDR outputs are used to drive the TCC solenoid.
Refer
to the
ECM QDR
check
procedure on the
facing page. This check will not test all ECM
functions, but it will determine if a specific circuit has
caused a specific QDR to fail in the ECM.
A faulty circuit is the largest cause of a failed
QDR, therefore, the check procedure should be used
whenever ECM replacement is indicated, especially if
the removed ECM exhibits characteristics of a
damaged QDR such as:
<" SES light with no code stored.
o Engine will not start and/or ECM will not
flash Code 12.
Flickering, intermittent, or dim SES light,
o Output, such as TCC circuit, is inoperative or
"ON" at all times,
o Engine misfires,
surges
or stalls.
€
1
"Scan"
tool is erratic or
inoperative.