8–6 Copyright © 1998 General Motors Corp.
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
TRANSMISSION DOES NOT
SHIFT PROPERLY (ROUGH
SHIFTS, SHIFTS OCCUR-
RING AT TOO LOW OR
TOO HIGH SPEED)
(cont’d)
Crossed wires in harness
Check for crossed wires and
correct
Intermittent problems Check wiring harnesses and
connectors (Appendix E)
Loose or damaged speed gear Replace output bearing nut
sensor retainer
Control spool valve sticking Overhaul valve body assembly
(refer to transmission Service
Manual)
Sticking stage 2 solenoid valve Overhaul valve body assembly
(refer to transmission Service
Manual)
RETARDER PERFORMANCE COMPLAINTS
A
. Retarder Does Not Apply Retarder enable input not activated Turn on retarder enable switch (if
present).
Retarder enable switch not working Replace retarder enable switch (if
present).
ABS input is active (if vehicle is
equipped with ABS)
None — This is normal. If ABS is
active, retarder will not apply.
Retarder request below
10.2 percent
Use DDR to determine counts
signaled by each RMR device
present. At least 15 counts are
required for some retarder apply
and 150–232 counts are required
for full apply. Replace RMR device,
based on test results.
Closed throttle not sensed Use DDR to check throttle signal.
Throttle must be below 9.8 percent
before retarder will apply. Readjust
or replace TPS.
Exception
: If TPS
has failed and Service Brake Status
input is sensed by ECU, the retarder
will still be applied.
Active code inhibiting retarder Correct cause for setting these
codes: 42 23, 44 23, 45 23, 46 26,
64 12, 64 23, or 69 29
Transmission output speed below
350 rpm (450 rpm for HD/B 500)
Raise output speed to above
350 rpm (450 rpm for HD/B 500)
Transmission not in a forward range Shift to a forward range
Table 8–1. Troubleshooting Performance Complaints
(cont’d)
Problem
Probable Cause Suggested Remedy
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