P0740 fault code: Torque Converter Clutch Circuit/Open

Last updated · OBDCode UK editorial

Can I drive with P0740? — Drive only if essential

Limit driving to essential journeys. Avoid long trips and heavy loads. Book diagnosis soon — if the car overheats, loses power, or feels unsafe, stop and arrange recovery.

P0740 means “Torque Converter Clutch Circuit/Open” — a transmission fault in the powertrain.

Can I DIY?

Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage.

Do not DIY this repairDIY boundary
ToolsBasic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

This fault is in the professional-only category. We do not publish strip-down or fitting steps on this page. Use a qualified garage.

P07xxTransmission
MOT fail riskif the warning light stays on

What does P0740 mean?

P0740 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P07xx block, which covers transmission. The stored description is “Torque Converter Clutch Circuit/Open”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0740 fail an MOT?

An illuminated engine management light is a Major defect at MOT since 2018 — an automatic fail until the fault is repaired and the light stays off. Clearing the code without fixing the cause is not a repair.

Before booking your test, check what usually fails on your car: see our MOT pass rates by make and model, built from 33.1 million DVSA tests.

What the MOT data says

No MOT certificate item corresponds to this code; MOT outcome data cannot be shown.

Related guides

Car diagnostic test cost: compare the scopeUK booking marketplaces currently publish diagnostic averages of about £52–£65. Engine management light on: steady or flashing?A steady engine management light means the computer has stored a fault. Drive with caution and get the code read. A flashing light is different — stop when it is safe.
P0700Transmission Control System (MIL Request) P0701Transmission Control System Range/Performance P0702Transmission Control System Electrical P0703Brake Switch 'B' Circuit P0704Clutch Switch Input Circuit Malfunction P0705Transmission Range Sensor Circuit Malfunction (PRNDL Input) P0706Transmission Range Sensor Circuit Range/Performance P0707Transmission Range Sensor Circuit Low

P0740 — quick answers

Is it safe to drive with P0740?

Drive only if essential. Limit driving to essential journeys. Avoid long trips and heavy loads. Book diagnosis soon — if the car overheats, loses power, or feels unsafe, stop and arrange recovery.

Can I fix P0740 myself?

Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage. Basic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

Will P0740 fail my MOT?

An illuminated engine management light is a Major defect at MOT since 2018 — an automatic fail until the fault is repaired and the light stays off. Clearing the code without fixing the cause is not a repair.

Fault-code identifiers are standard diagnostic facts. Their explanations and diagnostic guidance on this site are original editorial summaries, not reproduced SAE wording. MOT defect rules reflect the DVSA MOT inspection manual (2026). This page is general guidance for UK drivers, not a substitute for a professional diagnosis.