95 1/2 Model

This Diagnostic Trouble Code (DTC) flashes the "CHECK TRANS" Indicator and sets the Backup Mode.




Circuit Description
- The output speed information is used to determine if the Transmission has to be upshifted or downshifted.
- If this information suddenly changes due to an open circuit or some electrical interference the Transmission would downshift.
- To avoid this the Transmission Control Module (TCM) is constantly checking the variations of the output speed. If this variation is too great (too much decrease or increase) the DTC 62 is set. This variation is taken into amount only when the output speed is more than 2900 rpm (approx. 90 kph).
- The Transmission Output Speed Sensor provides information on Vehicle speed to the TCM. The Speed Sensor circuit consists of a magnetic induction type sensor. The sensor is mounted above a target wheel pressed on the output shaft in the Transmission extension. As the output variable voltage in the magnetic pickup. This alternating current (AC) signal is provided to the TCM. The voltage increases with the speed of the wheel but this is not used to define the speed of the Vehicle. As the Vehicle moves faster, the signal alternates faster between positive and negative voltages. The output speed information is proportional to the frequency of the signal.


CAUTION: If wire to connector A-63 terminal 812 is short to voltage, Transmission Control Module will be damaged.

Diagnostic Aids
- This diagnostic is not an electrical test done by the TCM but a test between different information ("logic test").

- Detection Conditions:
a. Variation of output speed is more than 512 rpm (approx. 16 kph)/0.025s.
b. Ignition is "ON" more than 5 seconds.
c. Mode Switch is not in P, N or R.
d. Last output speed is more than 2900 rpm.
e. The conditions need to be present for at least 0.1 seconds.

- Action After The Detection Time:
- Backup Mode.

- Recovery Conditions:
- To recover do an Ignition Cycle.








DTC 62 / Flow Charts