1st. Gear Malfunction
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0731 NISSAN Possible Causes
- Low transmission fluid level
- Dirty transmission fluid
- Shift solenoids
- Transmission mechanical problems
- Transmission hydraulic control circuit
How do I fix code P0731 NISSAN?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- There are Factory Service bulletins for the following Nissan models:
- 1995-1996 Nissan Maxima
- 1995-1997 Nissan Sentra/200SX
- 1996-1997 Nissan Truck
- 1995-1997 Nissan Altima
- 1996-1997 Nissan Pathfinder
- 1995-1996 Nissan 240SX
- 1996-1997 Nissan Quest
- Nissan Factory Service Bulletin OBDII Code P0731
- 2002 Nissan Sentra
- 2002 Nissan Altima
- 2002 Nissan Sentra and Altima Factory Service Bulletin OBDII Code P0731
Cost of diagnosing the P0731 NISSAN code
The cost of diagnosing the P0731 NISSAN code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
P0731 is detected when A/T cannot be shifted to the 1st gear position even if electrical circuit is good.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Incorrect transmission shifting
P0731 NISSAN Description
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.