8–4 Copyright © 1998 General Motors Corp.
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
ECU WILL NOT TURN OFF
WHEN IGNITION SWITCH
OFF
Faulty ignition switch Replace ignition switch
Externally-generated speed
sensor signal(s) (refer to
Appendix L for detailed
inspection)
Find source of false speed sensor
signal(s) and correct problem
TRANSMISSION WILL NOT
SHIFT TO FORWARD OR
REVERSE (STAYS IN
NEUTRAL)
Engine rpm too high Reduce engine rpm
Low fluid level Add fluid to proper level (refer to
transmission Mechanic’s Tips for
proper dipstick calibration)
Fluid temperature too low Warm fluid
Throttle position sensor or
linkage is not functioning
properly
Refer to throttle position sensor
for correct set-up (Appendix F)
Voltage to ECU too low Check vehicle battery and
charging system
Shift selector is not functioning
properly
Replace shift selector
Disconnected or dirty connectors Perform connector checkout
(Appendix E)
Faulty wiring harnesses Repair harness (Appendix E)
Speed sensor(s) not functioning
properly
Repair or replace speed sensor(s)
or circuitry (see transmission
Service Manual and Appendix E)
Faulty ECU Replace the ECU
Input function wire open and
auxiliary function range inhibit in
the calibration EEPROM
Check input function
programming with Pro-Link
®
.
Correct wiring or switch problem
which does not allow input
function wire to be grounded
TRANSMISSION WILL NOT
STAY IN FORWARD OR
REVERSE
Auto-neutral or quick-to-neutral
circuit (input function) faulty
Repair quick-to-neutral circuit
Leaking at solenoid assembly Rebuild solenoid assembly (see
transmission Service Manual)
Faulty solenoid — leaking Replace solenoid (see trans-
mission Service Manual)
Table 8–1. Troubleshooting Performance Complaints
(cont’d)
Problem
Probable Cause Suggested Remedy
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