P0731 OBD Code Definition:
P0731 Gear 1 Incorrect Ratio
P0731 OBD Code Description:

OBD Code P0731

Gear 1 Incorrect Ratio

What’s mean?

OBD2 Code P0731 Definition:
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.


Possible sumptoms of P0731
– Engine Light ON (or Service Engine Soon Warning Light) – Incorrect transmission shifting

Possible Causes

Possible causes of P0731
– Low transmission fluid level – Dirty transmission fluid – Shift solenoids – Transmission mechanical problems – Transmission hydraulic control circuit The Error code is generally activated on detection of the following conditions: P0731 is detected when A/T cannot be shifted to the 1st gear position even if electrical circuit is good.

Possible Solutions

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