6–94 Copyright © 1998 General Motors Corp.
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
Main code 54 indicates a failed oncoming ratio test. The ratio test after a shift is failed when the ECU has
commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and
output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If
conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is
logged and the DO NOT SHIFT response is commanded. If the code is set during a direction change, Neutral with
No Clutches is commanded, otherwise the transmission is commanded to the previous range. Main code 54 can
also be caused by the EEPROM being calibrated for a close ratio transmission and installed in a wide ratio
transmission, or vice versa. Additional codes could be logged for other shifts where “X” indicates the range from
and “Y” indicates the range to (there have been occurrences of Code 54 87, N1–R, for example).
NOTE: This test is not performed below a calibrated transmission output speed of 200 rpm.
Main
Code
Subcode Meaning
54 01 L–1 upshift
54 07 L–R shift
54 10 1–L downshift
54 12 1–2 upshift — incorrect calibration, wide ratio vs. close ratio
54 17 1–R shift
54 21 2–1 downshift
54 23 2–3 upshift
54 24 2–4 upshift
54 27 2–R shift
54 32 3–2 downshift
54 34 3–4 upshift
54 35 3–5 upshift
54 42 4–2 downshift
54 43 4–3 downshift
54 45 4–5 upshift
54 46 4–6 upshift
54 53 5–3 downshift
54 54 5–4 downshift
54 56 5–6 upshift
54 64 6–4 downshift
54 65 6–5 downshift
54 70 R–L shift
54 71 R–1 shift
54 72 R–2 shift
54 81 N1–1 shift
54 82 N1–2 shift
54 83 N1–3 shift
54 85 N1–5 shift
54 86 N1–6 shift
54 92 N2–2 shift
54 93 N3–3 shift
54 95 N3–5 shift
54 96 N4–6 shift
54 97 NVL–Reverse shift
54 XY X to Y shift
CODE 54 XX — ONCOMING RATIO TEST (AFTER SHIFT)
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