Pontiac Fiero 1988 Service Manual page 504

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI) 6E2-A-49
©
©CLEAR CODES.
e IDLE ENGINE FOR 1 MINUTE OR UNTIL CODE 42 SETS.
DOES CODE 42 SET?
CODE 42
ELECTRONIC SPARK TIMING (EST)
CIRCUIT
2.5L "P" SERIES (TBI)
©
YES
* IGNITION " O F F " .
i DISCONNECT ECM CONNECTORS.
MGNITION " O N " .
i OHMMETER SELECTOR SWITCH IN THE 1000 TO 2000 OHMS
RANGE.
I PROBE ECM HARNESS CONNECTOR CKT 423 WITH AN
OHMMETER TO GROUND.
IT SHOULD READ LESS THAN 500 OHMS.
DOES IT?
NO
CODE 42 INTERMITTENT. REFER TO
"DIAGNOSTIC AIDS" ON FACING PAGE.
©
©
Y E S
• PROBE ECM HARNESS CONNECTOR CKT 424 WITH A
TEST LIGHT TO 12 VOLTS AND NOTE LIGHT.
LIGHT " O F F "
© WITH OHMMETER STILL CONNECTED TO ECM HARNESS
CKT 423 AND GROUND. AGAIN PROBE ECM HARNESS CKT
424 WITH THE TEST LIGHT CONNECTED TO 12 VOLTS. ( A S
TEST LIGHT CONTACTS CKT 424, RESISTANCE SHOULD
SWITCH FROM UNDER 500 TO OVER 5,000 O H M S , )
DOES IT?
NO
© DISCONNECT DIS 6-WAY CONNECTOR . NOTE OHMMETER
THAT IS STILL CONNECTED TO CKT 423 AND GROUND.
RESISTANCE SHOULD HAVE GONE HIGH (OPEN CIRCUIT).
DOES IT?
©
YES
NO
CKT 424 OPEN, FAULTY
CONNECTIONS OR FAULTY
IGNITION MODULE.
CKT 423
SHORTED TO
GROUND.
NO
OPEN CKT 423, FAULTY CONNECTION
OR FAULTY IGNITION M O D U L E .
1
LIGHT " O N "
"I
9 DISCONNECT IGNITION MODULE 6-WAY CONNECTOR.
LIGHT " O N "
Z E Z Z Z
CKT 424 SHORTED
TO GROUND.
LIGHT " O F F "
" <
FAULTY IGNITION
M O D U L E .
YES
• RECONNECT ECM AND IDLE ENGINE FOR
ONE MINUTE OR UNTIL C O D E 42 S E T S .
DOES CODE SET?
YES
NO
FAULTY ECM
CODE 42 INTER-
MITTENT. REFER TO
"DIAGNOSTIC AIDS"
ON FACING PAGE.
84-85 CLEAR CODES AND CONFIRM " C L O S E D L O O P " OPERATION AND NO "SERVICE ENGINE S O O N " LIGHT.
* 7 S 3 1 5 3 - 6 E
2-25-87