[amidgeha]

Gear 1 Incorrect Ratio

This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:



Torque converter slip ratio = A x C/B

A: Output shaft revolution signal from revolution sensor

B: Engine speed signal from Engine Control Module (ECM)

C: Gear ratio determined as gear position which TCM supposes



If the actual gear position is higher than the position (1st) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.

Cause:
Low transmission fluid level
Dirty transmission fluid
Shift solenoids
Transmission mechanical problems
Transmission hydraulic control circuit

Symptoms:
Check engine light
Incorrect transmission shifting