Code Definition

P0734 — Gear 4 Incorrect ratio

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0734

P0734 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0734 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0734 fault code is set when the Transmission Control Module (TCM) detects that the actual ratio of gear 4 in the transmission is not aligning with the expected ratio specified by the manufacturer. This issue with the fourth gear ratio can significantly affect transmission operation, particularly when shifting into or maintaining fourth gear. Common causes for this fault code include mechanical wear or damage inside the transmission, problems with the transmission fluid, or issues related to transmission sensors. Symptoms might include difficulty in shifting into fourth gear, slipping or a...

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