P0731 on Audi
Gear 1 Incorrect Ratio
P0731 on Audi vehicles indicates gear 1 incorrect ratio. Au7o has documented this code across 4 Audi models — most commonly on 100, A4, 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 $10,000, 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(1 issue)
- CVT Multitronic Transmission Failure and PRNDS Flashing on Front-Wheel-Drive A42002-2008
Front-wheel-drive A4 models equipped with the Multitronic CVT have a long history of owner complaints involving shuddering from a stop, delayed engagement, limp mode, and flashing PRNDS indicators. Failures are commonly tied to the transmission control module, internal clutch pack wear, or CVT chain/pulley problems. The issue is widely discussed in Audi forums and complaint databases because repairs are expensive and many units require replacement or specialist rebuilding.
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.
Audi A6(1 issue)
- Multitronic CVT Transmission Failure2005-2011
The Multitronic CVT (continuously variable transmission) used in C6 A6 models is notoriously unreliable and prone to catastrophic failure between 80,000-150,000 miles. The transmission uses a steel chain and hydraulic pressure system that wears over time, causing slipping, shuddering, and complete failure. Symptoms include hesitation on acceleration, jerky shifts, whining noises, or sudden loss of drive. Unlike traditional automatics, CVT failures often require complete transmission replacement—repairs are not cost-effective. Audi discontinued the Multitronic in 2012 due to reliability issues. The transmission fluid is expensive ($30/liter) and requires changes every 40,000 miles, but even with perfect maintenance, failures are common. Many A6 owners in forums report Multitronic failures under 100,000 miles, with replacement costs exceeding the car's value.
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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 4 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 $10,000, depending on the specific model and root cause.
Which Audi models have P0731 documented?▼
Au7o has documented P0731 on 4 Audi models: 100, A4, A4 Avant, A6.