Copyright © 1998 General Motors Corp. 3–1
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
3–1. BASIC KNOWLEDGE REQUIRED
To service WT Series Electronic Controls, the technician must understand basic electrical concepts. Technicians
need to know how to use a Volt-Ohmmeter to make resistance and continuity checks. Most troubleshooting checks
consist of checking resistance, continuity, and checking for shorts between wires and to ground. The technician
should be able to use jumper wires and breakout harnesses and connectors. Technicians unsure of making the
required checks should ask questions of experienced personnel or find instruction.
The technician should also have the mechanical aptitude required to connect pressure gauges or transducers to
identified pressure ports used in the troubleshooting process. Pressure tap locations and pressure values are shown
in Appendix B — Checking Clutch Pressures.
Input power, ground, neutral start circuitry, etc., can cause problems with electronic controls or vehicle functioning
and may not generate a diagnostic code. A working knowledge of WT Series Electronic Controls vehicle
installation is necessary in troubleshooting installation-related problems.
Refer to Section 8 for information concerning performance complaints (non-code) troubleshooting. A complete
wiring schematic is shown in Appendix J. Refer to the MD, HD, B 300, and B 500 Series Sales Tech Data Book for
information concerning electronic controls installation and the Installation Checklist. Reliable transmission
operation and performance depend upon a correctly installed transmission. Review the Installation Checklist to
ensure proper installation.
NOTE: Allison Transmission is providing for service of WTEC II wiring harnesses and wiring harness
components as follows: (See Service Information Letter 1-WT-97 for further information.)
•
Repair parts for the internal wiring harness and for wiring harness components attached to the shift selector
will be available through the Allison Transmission Parts Distribution Center (PDC). Use the P/N from your
appropriate parts catalog or from Appendix E in this manual. Allison Transmission is responsible for
warranty on these parts.
•
Since January, 1998, all WTEC II external harnesses and external harness components must be obtained
from St. Clair Technologies Inc. (SCTI). SCTI provides parts to any Allison customer or OEM and is
responsible for warranty on these parts. SCTI recognizes ATD, manufacturers, and SCTI part numbers.
SCTI provides a technical HELPLINE at 519-627-1673 (Wallaceburg). SCTI has parts catalogs available.
The SCTI addresses and phone numbers for parts outlets are:
3–2. USING THE TROUBLESHOOTING MANUAL
Use this manual as an aid to troubleshooting the WT Series Electronic Controls. Every possible problem and its
solution cannot be encompassed by any manual. However, this manual does provide a starting point from which
most problems can be resolved.
Once a solution to a problem is discovered in the manual do not look further for other solutions. It is necessary to
determine
why
a problem occurred. For example, taping a wire that has been rubbing on a frame rail will not
correct the problem unless the rubbing contact is eliminated.
St. Clair Technologies, Inc.
1050 Old Glass Road
Wallaceburg, Ontario, Canada, N8A 3T2
Phone: (519) 627-1673
Fax: (519) 627-4227
St. Clair Technologies, Inc.
1111 Mikesell Street
Charlotte, Michigan 48813
Phone: (517) 541-8166
Fax: (517) 541-8167
St. Clair Technologies, Inc.
c/o Mequilas Tetakawi
Carr. Internationale KM 1969
Guadalajara – Nogales, KM2
Empalme, Sonora, Mexico
Phone: 011-52-622-34661
Fax: 011-52-622-34662
S
ECTION
3 — BASIC KNOWLEDGE
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