Honda Prelude 1993 Service Manual page 512

Electrical Troubleshooting
Troubleshooting Flowchart (cont'd)
Solt-diagnosls I D4 | indicatoi
lghl blinks tont-ime..
Turn the ignition switch ON.
Chock whethor the Malfunc_
tion Indicator Lamp (MlL)
blinks lse6 section 11).
Booah lho PGM-FI Syttem
l!.o 3oction 111.
Turn the ignition swhh OFF
Disconnect the 26P and W
connectors lrom the TCM.
C o n n e c t t h e T e s t H a r n e s s
"A" and "O" connoctors lo
th€ wire harness only, not to
the TCM(14-35).
Turn tho ignition switch ON.
Measure the vohage betwoen
the 018 ard A2tA26 termi-
na|s.
Ropair opon or rhort in LT
GRN/BLK wir. botween the O
18 t.rmin6l and tho ECM,
ls the vohag6 4.75-5.25V?
Turn the ignition switch OFF.
C o n n 6 c t t h e T 6 s t H a r n e s s
..A,. and ,,D,, connectols to
tho TCM.
Start th€ engino and warm it
up to normal op€rating temper-
ature (the radiator fan comes
on).
Measure the voha96 betwoen
the D5snd A2ryA26 terminals
Ropoil opon or short in YEL/
BLU wiro botvvsen the D5 tor_
mlnrl and th6 ECT !on3or.
ls the vohage l€ss than
'lV?
Possibl€ Cause
' Disconnacted engine coolant
t6mperature (ECT) sensor
connector
' Short or op6n in th€ ECT
sensor wire
' Fauhy ECT sensor
A?5
o o o o o o o o o o o
o o o o o o o o
o o o o o o o o o o o o
o o o o o o o o o o o o
o o o o o o o o o o o
o o o o o o o o o o o
o o o o o o o o o o o o
o o o o o o o o o o o o
check for loolo TCM connoc_
tor!. ll noce!.s.Y, subatitut6
a l n o w n - g o o d T C M s n d
aactEck.
14-50