GENERAL SYSTEM DIAGNOSTICS
SERVICE MANUAL NUMBER 23
90-861326--1 MARCH 1999 Page 5E-95
Discrete Input Circuit Check - Non-Scan 454 / 502 Mag MPI and 8.2L MPI Only
(4 of 5)
TESTING CIRCUITS FOR SHORT-TO-GROUND (–)
STEP
ACTION VALUE YES NO
PROCEED TO
1
1. Disconnect BLU/TAN wire from oil pres-
sure switch.
2. Disconnect BLU/TAN wire from gear lube
monitor.
3. Disconnect BLU/TAN wire from transmis-
sion temperature switch (if equipped).
4. Key “ON”, engine “OFF”.
Does audio warning buzzer sound?
Step 2 Step 3
2
1. Key “OFF”.
2. Disconnect ECM J1 connector.
3. Check for continuity between all wires
disconnected in “Step 1” and engine ground (–).
Is there continuity on BLU/TAN wire from
oil pressure switch?
Step 4 Step 3
Is there continuity on BLU/TAN wire from
gear lube switch?
Step 4 Step 3
Is there continuity on BLU/TAN wire from
transmission switch?
Step 4 Step 3
3 Circuit(s) is not shorted to ground (–). – –
4 Repair short-to-ground (–) in affected circuit. – –
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