BMW DTC P0734 – Gear 4 Incorrect Ratio
DTC P0734 meaning on BMW
The DTC P0734 code on a BMW indicates that there is an issue with the transmission’s fourth gear. The Powertrain Control Module (PCM) has detected that the actual gear ratio does not match the expected gear ratio for fourth gear.
BMW DTC P0734 symptoms
Symptoms of a DTC P0734 on a BMW may include harsh shifting, slipping in fourth gear, delayed engagement when shifting into fourth gear, decreased fuel efficiency, and the transmission may go into limp mode to prevent further damage.
BMW DTC P0734 causes
The most common causes of a DTC P0734 on a BMW include low transmission fluid level, dirty or contaminated transmission fluid, a faulty transmission solenoid, a worn clutch or clutch pack, a malfunctioning transmission control module, or mechanical issues within the transmission itself.
BMW DTC P0734 seriousness
Ignoring a DTC P0734 on a BMW can lead to further damage to the transmission and potentially result in a costly repair. It is important to address this issue promptly to prevent more severe transmission problems.
How to diagnose DTC P0734 on BMW
To diagnose a DTC P0734 on a BMW, a mechanic will typically start by using a scan tool to retrieve the trouble codes stored in the PCM. They will then inspect the transmission fluid level and condition, check for any leaks, perform a road test to observe the shifting behavior, and may conduct further tests such as a transmission pressure test or a clutch performance test.
How to fix DTC P0734 on BMW
Fixing a DTC P0734 on a BMW may involve topping up or replacing the transmission fluid, cleaning or replacing the transmission solenoid, repairing or replacing any damaged clutch components, recalibrating the transmission control module, or addressing any other underlying mechanical issues within the transmission.
How to erase DTC P0734 on BMW
Once the underlying issue causing the DTC P0734 on a BMW has been resolved, the code can be cleared using a scan tool. The mechanic can clear the code, and if the issue has been successfully fixed, the code should not return upon subsequent driving cycles.
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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