Copyright © 1998 General Motors Corp. 6–55
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
Main code 33 indicates the sump temperature sensor is providing a signal outside the usable range of the ECU.
This code indicates the sensor failed showing abnormally high or low temperature readings. Main code 33 can be
caused by a component or circuit failure or by extremely high or low temperatures. There are no operational
inhibits related to main code 33. The ECU assumes a hardware failure and that transmission temperatures are
normal (93ºC; 200ºF). Temperatures above or below normal cause poor shift quality.
NOTE: Code 33 23 in conjunction with Code 21 23 indicates the loss of common ground (wire 135) between
the throttle and temperature sensors.
Active Indicator Clearing Procedure:
•
Power down
•
Manual
•
Self-clearing
NOTE: Before troubleshooting, read Pages 6–17 and 6–18 of Section 6–5. Also, check the transmission
fluid level.
Troubleshooting:
1. If possible, check the sump temperature with a DDR. If a DDR is not available, use the shift
selector display to determine if the code is active (refer to Section 6–2). Disconnect harness at
ECU and check resistance of the sensor and compare with Figure 6–19.
2. If Step 1 reveals that the extreme temperature indication is no longer present, the temperature limit
could have been reached due to operational or ambient temperature extremes. Also, you may be
experiencing an intermittent problem and the code will not be active. Proceed cautiously, it is
unlikely there is a sensor hardware fault.
3. Disconnect the external harness at the transmission. Check the connectors and terminals for dirt,
corrosion, or damage. Clean or replace as necessary.
4. Check the sensor wires in the external harness for opens (Code 33 23), shorts between wires, or
shorts-to-ground (code 33 12 — refer to Section 4). If wiring problems are found, isolate and
repair as described in Appendix E.
5. If no harness problems are found check the feedthrough connector for damage. If the feedthrough
harness connector is satisfactory, drain the fluid and remove the control module. Check for chafing
of the sensor wires, especially near the separator plate. Eliminate the chafe point and repair the
wire as required. If no chafe point is found, replace the sensor (refer to the Transmission Service
Manual and Appendix E, Paragraph 1–14 in this Manual).
6. If the problem recurs, use spare wires in the external harness for the temperature sensor circuit.
7. 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.
Main
Code
Subcode Meaning
33 12 Temperature sensor failed low
33 23 Temperature sensor failed high
CODE 33 XX — SUMP OIL TEMPERATURE SENSOR
(Figures 6–17, 6–18)
To Next Page
Loading...