BMW DTC P0729 – Gear 6 Incorrect Ratio
DTC P0729 meaning on BMW
DTC P0729 indicates that the transmission control module (TCM) has detected an incorrect gear ratio in the 6th gear of a BMW vehicle. This means that the actual gear ratio does not match the expected gear ratio for 6th gear, leading to a potential issue with the transmission’s operation.
BMW DTC P0729 symptoms
Symptoms of DTC P0729 in a BMW may include harsh shifting, delayed shifting, slipping gears, decreased fuel efficiency, and the transmission going into limp mode. The vehicle may also exhibit a Check Engine Light on the dashboard.
BMW DTC P0729 causes
The most common causes of DTC P0729 in a BMW include low transmission fluid level, dirty or contaminated transmission fluid, a faulty transmission speed sensor, a malfunctioning shift solenoid, or internal transmission damage.
BMW DTC P0729 seriousness
Ignoring DTC P0729 in a BMW can lead to further damage to the transmission and potentially result in costly repairs. It is important to address this issue promptly to prevent more severe transmission problems in the future.
How to diagnose DTC P0729 on BMW
To diagnose DTC P0729 on a BMW, a mechanic will typically use a diagnostic scanner to retrieve the fault codes stored in the TCM. They will then perform a visual inspection of the transmission fluid level and condition, check the transmission speed sensor and shift solenoid for proper operation, and conduct a road test to observe the vehicle’s shifting behavior.
How to fix DTC P0729 on BMW
Fixing DTC P0729 on a BMW may involve topping up or replacing the transmission fluid, cleaning or replacing the transmission speed sensor, inspecting and repairing any damaged wiring or connectors, or replacing the shift solenoid if necessary. In some cases, internal transmission repairs may be required.
How to erase DTC P0729 on BMW
Once the underlying issue causing DTC P0729 has been addressed and fixed, the fault codes can be cleared using a diagnostic scanner. This will reset the Check Engine Light and allow the vehicle’s TCM to monitor the transmission for any new issues.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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