Copyright © 1998 General Motors Corp.
6–109
W T E C I I E L E C T RO N I C C O N T RO L S T RO U B L E S H O OT I N G M A N UA L
Code 63 00 is set when one of the two inputs for an input function Auxiliary Function Range Inhibit (Special) is in
a different state (on or off) from the other input for longer than two minutes. When this condition is detected,
Code 63 00 is set, the Service Indicator output is turned on. The transmission will not be inhibited in shifting from
neutral to range.
NOTE:
If Code 63 00 is set and the ECU was programmed after 9/26/94, the SERVICE icon on the shift
selector will be illuminated.
Subcode 26 is set when this function (Kickdown) is selected by calibration, the calibration designated input is active
but not failed, and throttle position is less than the calibration value defined. The kickdown shift schedule is inhibited
when subcode 26 is active. The service indicator will be turned on if it is selected by the calibration. The kickdown
shift schedule is not inhibited, the code is cleared and the service indicator will be turned off if the kickdown input
remains inactive for the calibration time period while throttle position is less than the calibration value.
Subcode 40 is set when this function (Service Brake Status) is selected by calibration, and the specified input
remains active for a calibration number of consecutive acceleration events. The service indicator will be turned on
if it is selected by the calibration. A vehicle acceleration event is defined as an increase in transmission output
speed from 1 rpm to a calibration value. The operation of the Automatic Neutral For Refuse Packer will be limited
when this code is active. The active inhibit for this code is self-cleared and the service indicator will be turned off if
the designated input for the Service Brake Status function becomes inactive.
Subcode 41 is set when the states of the calibration inputs are different for a calibration number of consecutive
updates. The inputs in this case are Pump/Pack Enable and Automatic Neutral For Refuse Packer. The service
display will also be turned ON if selected by calibration.
Active Indicator Clearing Procedure:
•
Power down
•
Manual — subcode 26 only
•
Self-clearing — subcode 26 only
Troubleshooting:
A.
Code 63 00
1. Use the DDR to identify the two input wires programmed with Auxiliary Function Range Inhibit
(Special). Inspect the input wiring, connectors, and switches to determine why the input states are
different. Correct any problems which are found.
2. 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
63
00
Auxiliary Function Range Inhibit (Special) inputs states are different
63
26
Kickdown input failed on
63
40
Service brake status failed on
63
41
Pump/pack and auto Neutral GPI failure
CODE 63 XX — INPUT FUNCTION FAULT
