DTC 85

DTC 85 Undefined Ratio Error:

Undefined Ratio Error:

Undefined Ratio Error:

CIRCUIT DESCRIPTION
The control module calculates ratio based on the transmission input speed and output speed sensor readings. The control module compares the known transmission ratio to the calculated ratio, for the particular gear range selected.

DTC 85 WILL SET WHEN
^ No DTC(s) 21, 22, 24, 28, 71, 72 and 87.
^ TP is greater than 25%.
^ Not in P/N or 4th gear.
^ Engine speed is greater than 300 rpm.
^ Vehicle speed is greater than 7 mph.
^ All conditions are met for 2 seconds.

ACTION TAKEN (PCM will default to)
^ Line pressure set to maximum.
^ Inhibits TCC operation.

DTC 85 WILL CLEAR WHEN
The condition no longer exists, and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. An out of range trans range pressure switch could falsely indicate the actual transmission range.
2. This test checks the calculated ratio to determine if the ratio is within the parameters.

DIAGNOSTIC AIDS
DTC 85 will set when an unknown gear ratio is detected for any gear but 4th. Note commanded gear and incorrect ratio. Check transmission fluid level.