Copyright © 1998 General Motors Corp. 6–93
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
Troubleshooting:
1. Be sure the transmission is warm and the fluid level is correct. Correct transmission fluid level
as necessary.
2. Using the DDR, check the engine and turbine speed sensor signals under steady conditions. If a
tachometer is available, compare the tachometer reading with the engine rpm reading on the
diagnostic tool. Check signals in neutral, at idle, high idle and maximum no load rpms. If a signal
is erratic, check sensor wiring for opens, shorts, and shorts-to-ground (refer to Code 22 XX).
Check all connections for dirt and corrosion. If wiring problems are found, repair or replace as
necessary. See Appendix E for connector service information.
3. If fluid and wiring are satisfactory, install a pressure gauge in the pressure tap for the offgoing
clutch. Make the shift indicated by the code using the clutch test mode of the Pro-Link
®
diagnostic
tool. If the pressure gauge shows clutch pressure (above 55 kPa or 8 psi) remains in the offgoing
clutch, drain the fluid and remove the control module (see the transmission Service Manual).
Disassemble and clean the control module and check for damaged valve body gaskets and stuck or
sticky valves, particularly latch valves and solenoid second-stage valves.
4. If excessive clutch pressure is not remaining in the offgoing clutch, replace the engine speed
sensor and the turbine speed sensor (refer to the transmission Service Manual).
5. If the control module is removed to replace the turbine speed sensor (MD, B 300, B 400), clean the
control module and inspect for stuck or sticky valves (particularly the latch valves and solenoid G
second stage valve). Check the rotating clutch drum to which the turbine speed sensor is directed
for damage, contamination, or signs of contact between the drum and the sensor.
6. If the problem recurs, replace the solenoid(s) for the offgoing clutch(es) (refer to the transmission
Service Manual).
7. If the problem again recurs, the offgoing clutch must be held on mechanically (coned, burned, etc.).
Remove the transmission and repair or rebuild as necessary (see the transmission Service Manual).
8. If the condition persists, replace the ECU. If replacing the ECU corrects the problem, reinstall the
original (bad) ECU to confirm that the problem is in the ECU. If the original ECU now works,
inspect the ECU connectors for any corrosion or damage which may cause an intermittent
condition. If the original problem recurs, reinstall the replacement ECU.
CODE 53 XX — OFFGOING SPEED TEST (DURING SHIFT)
To Next Page
Loading...