8–8 Copyright © 1998 General Motors Corp.
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
C
. Vehicle Moves Forward in
Neutral*
C1 clutch failed or not released Rebuild C1 clutch (refer to
transmission Service Manual )
D
. Vehicle Moves
Backward in Neutral*
C3 clutch failed or not released Rebuild C3 clutch assembly
(refer to transmission Service
Manual)
EXCESSIVE FLARE —
ENGINE OVERSPEED ON
FULL-THROTTLE UPSHIFTS
TPS Adjustment:
— Overstroke — Adjust TPS linkage for proper
stroke (see Appendix F)
— Loose — Tighten loose bolts or
connections
Incorrect calibration Correct calibration
ECU input voltage low Check electrical system and all
connections from battery and
ECU
Incorrect fluid level Add fluid to proper level (refer to
transmission Mechanic’s Tips for
proper dipstick calibration)
Low main pressure See Low Pressure section
Erratic speed sensor signal See Code 22 XX
Sticking stage 2 solenoid valve
(see Solenoid and Clutch
sections)
Clean and repair stage 2 valve
(refer to transmission Service
Manual)
Piston seals leaking or clutch
plates slipping in range involved
(see Range Clutch
Troubleshooting section)
Overhaul transmission (refer to
transmission Service Manual)
RANGE CLUTCH TROUBLESHOOTING SECTION
EXCESSIVE SLIPPAGE AND
CLUTCH CHATTER
Incorrect calibration Verify calibration
ECU input voltage low Check power, ground, charging
system, and battery functions
Throttle position sensor out of
adjustment or failed
Adjust or replace throttle position
sensor (refer to Appendix F)
Incorrect speed sensor readings See Code 22 XX
Table 8–1. Troubleshooting Performance Complaints
(cont’d)
Problem
Probable Cause Suggested Remedy
* See explanation of NVL in Section 2–3
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