Pontiac Fiero 1988 Service Manual page 572

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI) 6 E 2 - C 1 0 - 3
• IGN "OH", ENGINE " O F F " .
• TORN A/C ON AND OFF AND NOTE A/C CLUTCH,
o
CLUTCH
SHOULD
NOT CYCLE
ON AND OFF.
• DOES IT?
CHART C-10
A/C CLUTCH CONTROL
2.5L "P " SERIES (TBI)
NO
YES
• WITH ENGINE IDLING AT NORMAL
OPERATING TEMP. TURN A/C ON AND OFF.
• CLUTCH SHOULD CYCLE ON AND OFF.
© DOES IT?
© DISCONNECT A/C RELAY.
• PROBE CKT 458 WITH A
TEST LIGHT TO 12 VOLTS.
NO
I Z
PLACE A/C CONTROL IN A/C
MODE.
" S C A N " T O O L SHOULD
DISPLAY A/C REQUEST "ON"
DOES IT?
YES
DOES ENGINE COOLING
FAN OPERATE WITH A/C
" O N " , ENGINE IDLING?
LIGHT 1
J L _
ON"
LIGHT " O F F "
CKT 458 SHORTED
TO GROUND OR
FAULTY ECM.
FAULTY
RELAY.
YES
NO TROUBLE FOUND;
REVIEW SYMPTOMS FOR
BASIC A/C PROBLEM
NO
CHECK FOR:
- OPEN CKT 901
- ECM CONN. A T B 2 4 . IF
OK, SEE CHART C-12.
YES
•
IGN "ON", A/C " O N " .
• ENGINE " O F F " .
• DISCONNECT A/C RELAY
• PROBE HARNESS TERMINAL A&D
WITH TEST LIGHT TO GROUND.
NO
• I T
• IGNITION " O N "
• ENGINE " O F F "
© DISCONNECT LOW PRESSURE SWITCH.
© PROBE CKT 66 WITH A TEST LIGHT TO
GROUND.
LIGHT " O N " BOTH NO LIGHT,
ONE OR BOTH
LIGHT " O N "
JUMPER CKT 922
TO CKT 59.
DOES A/C CLUTCH
ENGAGE?
REPAIR OPEN
IN CKT THAT
DID NOT
LIGHT.
JUMPER HARNESS
TERMINALS TOGETHER.
" S C A N " SHOULD DISPLAY
A/C REQUEST " O N " .
DOES IT?
LIGHT " O F F "
x z = z z z
OPEN OR SHORT TO GND
IN CKT 66. IF A/C FUSE IS
BLOWN, CHECK CKTS 66,
6 7 , 9 0 1 , 9 2 2 AND 59 FOR
SHORT TO GND.
YES
NO
NO
ENGINE IDLING, A/C "ON"
PROBE CKT 458 WITH A
TEST LIGHTTO 12 VOLTS.
CHECK FOR OPEN:
- C K T 5 9 TO
CLUTCH.
- CLUTCH COIL
- G R O U N D C K T 1 5 0
I
YES
DISCONNECT HIGH PRESSURE
SWITCH.
JUMPER HARNESS TERMINALS
TOGETHER. DOES " S C A N "
DISPLAY A/C REQUEST
"ON"?
I
A/C S Y S T E M LOW ON
CHARGE, FAULTY
CONN., OR FAULTY LOW
PRESSURE SWITCH.
LIGHT "ON"
I
LIGHT " O F F "
FAULTY
RELAY.
OPEN OR SHORT TO VOLTAGE IN
C K T 4 5 8 , FAULTY CONNECTION,
OR ECM.
NO
ZEZ
YES
OPEN CKT 901 OR 67,
FAULTY ECM CONNECTOR
OR ECM
I
FAULTY
SWITCH OR
CONNECTOR
4-27-87
7S 3673-6E