P0729 on Acura
Gear 6 Incorrect Ratio
P0729 on Acura vehicles indicates gear 6 incorrect ratio. Au7o has documented this code across 1 Acura model — most commonly on MDX. P0729 means the transmission control system detected an incorrect gear ratio in 6th gear — the computer compares input shaft speed to output shaft speed and found the resulting ratio doesn't match what 6th gear should produce. This usually indicates the transmission is slipping in that gear, a clutch or band isn't holding, or a hydraulic/solenoid control problem is preventing proper engagement. You may feel slipping, flaring RPM, harsh shifts, or the transmission dropping into limp mode. Low fluid and worn internal components are frequent contributors.
Common Causes of P0729
- •Low or contaminated transmission fluid
- •Worn or slipping clutches/bands inside the transmission
- •Faulty shift solenoid or pressure control solenoid
- •Valve body wear or sticking valves
- •Failing torque converter
- •Internal mechanical wear or damage
- •Speed sensor fault giving incorrect ratio calculation
P0729 on Acura by Model
Acura MDX(1 issue)
- ZF 9-Speed Transmission Hesitation, Hard Shifts and Stalling (2016-2019 MDX)2016-2019
The ZF 9HP 9-speed automatic introduced on the 2016 MDX suffers from documented hesitation, harsh shifts, lurching, and unexpected downshifts/deceleration. Drivers report the vehicle hesitating from a stop, banging into gear, or briefly losing power. Software miscommunication between TCM, ECM and throttle control is the alleged root cause; a class action was filed alleging Honda knew of the defect from 2015.
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What does P0729 mean on Acura?▼
P0729 stands for "Gear 6 Incorrect Ratio." P0729 means the transmission control system detected an incorrect gear ratio in 6th gear — the computer compares input shaft speed to output shaft speed and found the resulting ratio doesn't match what 6th gear should produce. This usually indicates the transmission is slipping in that gear, a clutch or band isn't holding, or a hydraulic/solenoid control problem is preventing proper engagement. You may feel slipping, flaring RPM, harsh shifts, or the transmission dropping into limp mode. Low fluid and worn internal components are frequent contributors. On Acura specifically, this code is documented across 1 model.
What causes P0729 on Acura vehicles?▼
Common causes on Acura: Low or contaminated transmission fluid, Worn or slipping clutches/bands inside the transmission, Faulty shift solenoid or pressure control solenoid, Valve body wear or sticking valves, Failing torque converter. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0729 on a Acura?▼
Repair costs vary widely depending on the root cause and specific Acura model.
Which Acura models have P0729 documented?▼
Au7o has documented P0729 on 1 Acura model: MDX.