Copyright © 1998 General Motors Corp. 8–5
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
TRANSMISSION WILL NOT
MAKE A SPECIFIC SHIFT
Low engine power Correct engine problem, see
Engine Service Manual
Incorrect fluid level Correct fluid level (refer to
transmission Mechanic’s Tips for
proper dipstick calibration)
Extreme fluid temperature Inspect cooling system and fluid
level
Faulty speed sensor/circuit Repair circuit or replace speed
sensor(s) (see Code 22 XX)
Faulty temperature sensor/circuit Check for temperature reading
which inhibits shifts
Faulty shift selector Replace shift selector
Hydraulic problem Refer to Range Clutch
Troubleshooting section
Faulty ECU Replace ECU
TRANSMISSION DOES NOT
SHIFT PROPERLY (ROUGH
SHIFTS, SHIFTS OCCUR-
RING AT TOO LOW OR
TOO HIGH SPEED)
Engine idle speed too fast
(neutral to range shift)
Adjust engine idle speed (refer to
Vehicle Service Manual)
Faulty throttle sensor/circuit Refer to throttle sensor section
for installation and operation
information (Appendix F)
ECU input voltage low Check power, ground, charging
system, and battery function
Incorrect shift calibration for
vehicle
Install correct calibration
Instrument panel tachometer
incorrect
Repair or replace tachometer
Incorrectly calibrated electronic
speedometer
Calibrate electronic speedometer
Faulty speed sensor/circuit Repair circuit or replace speed
sensor (see Code 22 XX)
Loose speed sensor Tighten speed sensor retaining
bracket bolt
Incorrect fluid level Correct fluid level (refer to
Mechanic’s Tips for proper
dipstick calibration)
Table 8–1. Troubleshooting Performance Complaints
(cont’d)
Problem
Probable Cause Suggested Remedy
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