ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY) - 5E-10990-823225--1 1096
Code 42: IC Circuit (Scan)
(2 of 2)
DIAGNOSTIC AIDS:
Refer to “Intermittents” in “Troubleshooting.”
An intermittent problem may be caused by a poor or
corroded connection, rubbed through wire connec-
tion, a wire that is broken inside the insulation, or a
corroded wire.
Any circuitry that is suspected as causing the inter-
mittent complaint should be thoroughly checked for
backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, corroded terminals
and/or wiring, or physical damage to the wiring har-
ness. After repairs, clear codes following “Clearing
Codes” in “ECM Self-Diagnostics.” Failure to do so
may result in codes not properly being cleared.
LIGHT “OFF”
YES NO
• DISCONNECT IGNITION MODULE 4-WAY CONNECTOR.
1
3
• WITH OHMMETER STILL CONNECTED TO ECM HARNESS CKT
423 AND GROUND, AGAIN PROBE ECM HARNESS CKT 424
WITH THE TEST LIGHT CONNECTED TO BATTERY VOLTAGE.
(AS TEST LIGHT CONTACTS CKT 424, RESISTANCE SHOULD
SWITCH FROM OVER 3000 TO UNDER 1000 OHMS.)
DOES IT?
• CLEAR CODES.
• IDLE ENGINE FOR 1 MINUTE OR UNTIL CODE 42 SETS.
DOES CODE 42 SET?
CODE 42 INTERMITTENT. REFER TO
“DIAGNOSTIC AIDS” ABOVE.
2
YESNO
• DISCONNECT DIST. 4-WAY CONNECTOR. NOTE
OHMMETER THAT IS STILL CONNECTED TO CKT
423 AND GROUND. RESISTANCE SHOULD HAVE
GONE HIGH (OPEN CIRCUIT).
DOES IT?
• RECONNECT ECM AND IDLE ENGINE FOR
ONE MINUTE OR UNTIL MALFUNCTION IN
DICATOR “ON.”
YES NO
CKT 424 OPEN. FAULTY
CONNECTIONS OR FAULTY
IGNITION MODULE.
CKT 423
SHORTED TO
GROUND.
• IGNITION “OFF.”
• DISCONNECT ECM CONNECTORS.
• IGNITION “ON.”
• USE DVM WITH SELECTOR IN OHMS RANGE.
• PROBE ECM HARNESS CONNECTOR CKT 423 WITH
DVM TO GROUND.
IT SHOULD READ MORE THAN 3000 OHMS.
DOES IT?
YES NO
OPEN CKT 423. FAULTY CONNECTION
OR FAULTY IGNITION MODULE.
• PROBE ECM HARNESS CONNECTOR CKT 424 WITH
A TEST LIGHT TO BATTERY VOLTAGE.
LIGHT “ON”
45
LIGHT “ON” LIGHT “OFF”
CKT 424 SHORTED
TO GROUND.
FAULTY IGNITION
MODULE.
YES
NO
FAULTY ECM
CODE 42 INTERMITTENT.
REFER TO “DIAGNOSTIC
AIDS” ON FACING PAGE.
NOTE:CLEAR DIAGNOSTIC TROUBLE CODE (DTC) STOP ENGINE FOR AT LEAST ONE MINUTE AFTER REPAIR IS PER-
FORMED. RESTART ENGINE AND CHECK FOR CODES.
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