6–92 Copyright © 1998 General Motors Corp.
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
Main code 53 indicates a failed offgoing speed test. The speed test during a shift is designed to ensure neutral is
attained during shifts to neutral. This test compares engine speed to turbine speed. If neutral is selected and turbine
speed is found to be much lower than engine speed, the ECU sees this as neutral not being attained. The
transmission is commanded to Neutral with No Clutches and Code 53 XX is set. Additional codes could be logged
for other shifts where “X” indicates the range from and “Y” indicates the range to.
NOTE: This test is not performed if neutral output is below 200 rpm or when temperatures are below a
calibrated 0°C (32°F).
Active Indicator Clearing Procedure:
• Power down
• Manual — subcodes 78 and 99 only
NOTE: Before troubleshooting, read Pages 6–17 and 6–18 of Section 6–5. Also, check battery and ECU input
voltages.
NOTE: Intermittent connections or lack of battery-direct power and ground connections may cause this and
other codes.
NOTE: Energizing the solenoids and listening for ball/plunger movement is sometimes useful in
troubleshooting.
Main
Code
Subcode Meaning
53 08 L–N1 shift
53 09 Low–NNC shift
53 18 1–N1 shift
53 28 2–N1 shift
53 29 2–N2 shift
53 38 3–N1 shift
53 39 3–N3 shift
53 48 4–N1 shift
53 49 4–N3 shift
53 58 5–N1 shift
53 59 5–N3 shift
53 68 6–N1 shift
53 69 6–N4 shift
53 78 R–N1 shift
53 99 N3–N2 or N2–N3 shift
53 XY X to Y shift
CODE 53 XX — OFFGOING SPEED TEST (DURING SHIFT)
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