Open Loop Switch Test - Jeep 1987 Wrangler Workshop Manual

JP1
ENGINES
dps
FUEL FEEDBACK SYSTEMS
DIAGNOSTIC TEST 3
NOTE: ENGINE SHOULD BE AT NORMAL OPERATING
TEMPERATURE. ALL CONTINUITY TESTING SHOULD
BE DONE WITH MCU DISCONNECTED.
OPEN LOOP SWITCH TEST
NOTE: CONTINUITY TESTING WITH MCU CONNECTED
TO THE SYSTEM SHOULD INDICATE 2 OHMS. WHEN
THE MCU IS DISCONNECTED FROM THE SYSTEM.
ALL CONTINUITY SHOULD INDICATE LESS THAN 1
OHM. WHEN APPLICABLE, DIAGNOSTIC CONNECTOR
TERMINALS CAN BE USED AS TEST POINTS INSTEAD
OF MCU HARNESS CONNECTOR TERMINALS.
I
TUF
I
FRC
TURN E N G I N E OFF. USING A STANDARD VOLT-OHMMETER. TEST FOR CONTINUITY
FROM THE DIAGNOSTIC CONNECTOR PIN 7 TO MCU CONNECTOR PIN 20
NO
DISCONNECT VACUUM
HOSE FROM SWITCH 2 OF
VACUUM SWITCH
ASSEMBLY.
YES
TEST FOR CONTINUITY
BETWEEN DIAGNOSTIC
CONNECTOR PIN 12 AND
MCU CONNECTOR PIN
20
TRAPPED^
.VACUUM,
?
NO
YES
REPAIR MALFUNCTION
AND RETEST.
DISCONNECT VACUUM
SWITCH ASSEMBLY WIRE
CONNECTOR AND RETEST.
DISCONNECT COOLANT
TEMPERATURE SWITCH
CONNECTOR AND RETEST.
REPLACE VACUUM SWITCH
ASSEMBLY AND RETEST.
DISCONNECT MCU
HARNESS CONNECTOR
AND RETEST.
REPLACE COOLANT
TEMPERATURE SWITCH
AND RETEST
DISCONNECT MCU
CONNECTOR AND RETEST.
^ O P E N \ VES
vCIRCUIT/
7
REPLACE MCU AND
RETEST.
REPAIR HARNESS SHORT
CIRCUIT BETWEEN
VACUUM SWITCH
ASSEMBLY AND MCU.
RETEST.
CONT'D.
REPAIR HARNESS SHORT
CIRCUIT BETWEEN
COOLANT TEMPERATURE
SWITCH AND MCU.
RETEST.
81131AM)