PGM-FI System
MIL Circuit Troubleshooting (cont'd)
1 . Turn the ignition switch OFF.
I n s p e c t t h e A C G S ( 1 5 A ) f u s e i n t h e m a i n u n d e r -
hood fuse/relay box.
ls the f use OK?
YES Go to step 9.
NO - Check for these problems.l
. A s h o n i n t h e w i r e b e t w e e n t h e A C G S ( 1 5 A ) f u s e
a n d t h e P G M - F l m a i n r e l a y .
. A short in the wire between the PGM-FI main
relay and the ECM, injectors, or IAC valve.
I n s p e c t t h e N o . 2 F U E L P U M P S R S ( 1 5 A ) f u s e i n t h e
under-dash f use/relay box.
ls the f use OK?
YES Go to step '10.
NO Check for these problems. I
. A s h o r t i n t h e w i r e b e t w e e n t h e N o . 2 F U E L
P U M P S R S ( 1 5 A ) f u s e a n d t h e P G M - F l m a i n r e l a y
o r t h e S R S u n i t .
. A short in the wire between the PGM-Fl main
relay and the fuel pump.
. A faulty PGM-Fl main relay or faulty fuel pump.
9 .
11-82
1 0 .
D i s c o n n e c t E C N 4 c o n n e c t o r C { 3 1 P ) .
Check for continuity between body ground and
E C M c o n n e c t o r t e r m i n a l s C 1 9 a n d C 2 8 i n d i v i d u a l l y .
ECM CONNECTOR C (31PI
1 1 .
12.
2
5
7
8
I
t0
11 12
t 3
1 4
r5
1 7
1 8
2A 21 22
24
25
26 27 28
n
30
vcc2
(YEL/BLU)
vccl
o(O
W i r e s i d e o f f e m a l e t e r m i n a l s
(YEL/BEDI
ls there continuity?
YES Go to step 12.
N O G o t o s t e p 1 3 .
Disconnect the 3P connector from each of these
sensors, one at a time, and check for continuity
between body ground and ECM connector terminal
C 1 9 a n d C 2 8 i n d i v i d u a l l y .
. MAP sensor
. Vehicle speed sensor (VSS)
. Fuel tank pressure {FTP) sensor
. TP sensor
. A i r p u m p e l e c t r i c a l c u r r e n t s e n s o r
Is therc continuity?
YES Repair shon to body ground in the wire
b e t w e e n t h e E C M ( C 1 9 ) a n d t h e M A P s e n s o r , o r t h e
ECM (C28) and the TP sensor, VSS, FTP sensor or
a ; r p u m p e l e c t r i c a l c u r r e n t s e n s o r .
NO Replace the sensor that made continuity to
body ground go away when disconnected.l
Disconnect the injectors and IAC valve connectors.