REFERENCE INFORMATION
TRANSMISSION
SYSTEM
DTC 85
Undefined Ratio Error
DTC 87
High Ratio Error
Circuif Descriptions
The control
module calculates ratio based on the
transmission input speed and output speed sensor
reading. The control module compares the known
transmission ratio to the calculated ratio for the
particular gear range selected.
DTC 85 Will Set When-
* Throttle position is greater than 25%.
l Not in park, neutral, or 4th gear.
l Engine speed is greater than 300 r-pm.
l Vehicle speed is greater than 7 mph (11 kphl.
I COMMANDED
lFCAlCUlATEDRATlOIS:
I
GEAR
I
LESS THAN
I MORE THAN I
I
1st
I
2.38
I
2.63
I
I
2nd
I
1.43
I
1.58
I
I
3rd
I
0.95
I
1.05
I
I
REV
I
1.97
I
2.17
I
l All conditions are met for 2 seconds.
-
DTC 86
Low Ratio Error
Circuit Description:
The control module calculates ratio based on the
TISS and TOSS readings. The control module
compares the known transmission ratio to the
calculated ratio for the particular gear range
selected.
DTC 86 Will Set Whenr
l Not in park, reverse, or neutral.
l Engine speed is greater than 300 x-pm.
l Throttle position is greater than 25%.
l Vehicle speed is greater than 7 mph (11 kphl.
l Transmission gear ratio is less than 1.06 in
1st or 2nd gear,
l All conditions are met for 2 seconds.
TM 9-2320-387-24-l
Circuit Description:
The control module calculates ratio based on the TISS
and TOSS readings. The control module compares the
known transmission ratio to the calculated ratio for
the particular gear range selected.
DTC 87 Will Set When-
* Throttle position is greater than 25%.
l Not in park, reverse, or neutral.
l Engine speed greater than 300 rpm.
l Vehicle
speed
is
greater than 7 mph (11 kphl.
l Transmission temperature is greater than
68°F (20°C).
l All conditions are met for 2 seconds.
2-401
