P0731 on Audi
Gear 1 Incorrect Ratio
P0731 on Audi vehicles indicates gear 1 incorrect ratio. Au7o has documented this code across 2 Audi models — most commonly on 100, A4 Avant. This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 1st gear. The module compares input (engine/turbine) speed to output shaft speed; when the car is commanded into 1st but the calculated ratio doesn't match the expected value, P0731 sets. This points to slipping, an incorrect shift, or a hydraulic/mechanical problem rather than just an electrical fault. You may feel slipping, harsh or delayed engagement, or the transmission may go into a limited 'limp' mode. Typical repair costs on Audi range from $300 to $6,000, depending on the specific model and root cause.
Common Causes of P0731
- •Low or degraded/burnt transmission fluid
- •Slipping clutch packs or worn friction components
- •Stuck or faulty shift solenoid affecting 1st gear
- •Internal hydraulic leak / valve body fault
- •Worn or failing torque converter
- •Faulty input or output speed sensor
- •Mechanical wear (planetary gears, bands) inside the transmission
P0731 on Audi by Model
Audi 100(1 issue)
- Automatic Transmission Harsh Shifting1990-1994
The Audi 100/200 automatic transmission develops harsh shifting patterns and delayed engagement. The multi-plate clutches and valve body solenoids wear, particularly in higher-mileage examples.
Audi A4 Avant(1 issue)
- Multitronic CVT Transmission Failure2002-2008
The Multitronic CVT used in front-wheel drive A4 Avants is prone to premature failure of the chain, pulleys, and control unit. This transmission has a poor reliability record and is expensive to repair.
Looking for P0731 on a different make?
View P0731 across all makes →Frequently Asked Questions
What does P0731 mean on Audi?▼
P0731 stands for "Gear 1 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 1st gear. The module compares input (engine/turbine) speed to output shaft speed; when the car is commanded into 1st but the calculated ratio doesn't match the expected value, P0731 sets. This points to slipping, an incorrect shift, or a hydraulic/mechanical problem rather than just an electrical fault. You may feel slipping, harsh or delayed engagement, or the transmission may go into a limited 'limp' mode. On Audi specifically, this code is documented across 2 models.
What causes P0731 on Audi vehicles?▼
Common causes on Audi: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction components, Stuck or faulty shift solenoid affecting 1st gear, Internal hydraulic leak / valve body fault, Worn or failing torque converter. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0731 on a Audi?▼
Repair costs on Audi range from $300 to $6,000, depending on the specific model and root cause.
Which Audi models have P0731 documented?▼
Au7o has documented P0731 on 2 Audi models: 100, A4 Avant.