TransmissionGeneric OBD-II codeUrgency: Garage soon
Code P0740: torque converter clutch circuit fault
P0740 means: torque converter clutch circuit malfunction (TCC).[1][2] The torque converter of an automatic gearbox has a clutch (the lock-up clutch, or TCC) which, at cruising speed, connects the engine to the gearbox input so that there is no slip. The gearbox control unit operates it with a solenoid. P0740 indicates that it has detected an abnormality in the circuit of that solenoid, according to CódigosDTC. AutoDTCs specifies that this is an open or short-circuited solenoid or wiring, or a clutch commanded to lock without the engine and turbine speeds converging.[1][2]
What code P0740 means
The torque converter of an automatic gearbox has a clutch (the lock-up clutch, or TCC) which, at cruising speed, connects the engine to the gearbox input so that there is no slip. The gearbox control unit operates it with a solenoid. P0740 indicates that it has detected an abnormality in the circuit of that solenoid, according to CódigosDTC. AutoDTCs specifies that this is an open or short-circuited solenoid or wiring, or a clutch commanded to lock without the engine and turbine speeds converging.[1][2]
According to AutoDTCs, the code is usually confirmed after repeating over several driving cycles, so if it is stored it indicates a persistent fault. CódigosDTC refers to the manufacturer to identify the specific system.[1][2]
P0740 refers to the converter clutch solenoid circuit. P0741, which AutoDTCs titles “circuit performance”, is a different code and has its own page.[1]
Original definition (SAE J2012): Torque Converter Clutch Circuit Malfunction[1][2]
Causes of P0740
From most to least likely, according to the sources.
- 1Torque converter clutch (TCC) solenoid faulty or with an open circuit. AutoDTCs identifies it as the most common single cause.[1][2][3]
- 2Damaged, chafed or corroded connector wiring that cuts the solenoid circuit.[1][3]
- 3Low, burnt or contaminated gearbox oil, or the wrong level, which affects the solenoid and the valve body.[1][2][3]
- 4Valve body or TCC control valve stuck, worn or with a blocked passage, which does not let the apply pressure through.[1]
- 5Worn or damaged torque converter clutch, or internal gearbox wear that prevents lock-up.[1][2]
- 6Other gearbox faults: torque converter, gearbox pump or blocked filter (Rerev).[3]
Symptoms
- Engine fault warning light on; on some cars the overdrive or gearbox warning too.[1][2][3]Engine warning light: faults that cause it
- Higher fuel consumption, especially on the road, because the converter keeps slipping.[1][2][3]Uses more fuel: faults that cause it
- Higher than normal revs at a steady speed, instead of dropping when the converter should lock.[1]
- Jerking, vibration or juddering at around 40–55 mph (about 65–90 km/h), according to AutoDTCs.[1]
- Overheating of the gearbox oil.[1][2]
- Abrupt or erratic shifts, slipping, weak acceleration and gearbox whining noises.[3]
How to diagnose P0740
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the gearbox codes and save the freeze frame data (speed, temperature, accelerator position) before clearing anything. Deal first with any code for another solenoid or pressure switch.[1][3]
- 2Check the oil level and condition: it should be clean and reddish, not dark, watery or smelling burnt. Correct the oil according to the manufacturer before blaming the electrical part.[1][2]
- 3Inspect the wiring and connector between the control unit and the gearbox: chafing, corrosion, open terminals or oil ingress. Move the harness with a multimeter connected to detect intermittent faults.[1][2]
- 4With the ignition off, measure the solenoid's resistance and compare it with the manufacturer's figure (AutoDTCs cites about 10 to 15 ohms in many units, but the exact value must be confirmed). Infinity suggests an open circuit, and close to zero a short circuit. Also check the earth and the control signal.[1]
- 5With the diagnostic equipment, command the lock-up and check the converter slip, which should approach zero. If it does not drop, suspect the valve body, the control valve or the converter, and carry out a hydraulic pressure test before opening the gearbox.[1][3]
Can I keep driving with P0740?
Garage soon
AutoDTCs rates it as moderate: it can be driven for a short time, but it should be repaired soon, because without lock-up the consumption rises and the gearbox works hotter, which accelerates its wear. Rerev does not recommend continuing to drive with the code, because it can cause more damage to the gearbox and make the repair more expensive. The prudent course is to take the car to a workshop as soon as possible.[1][3]
Documented faults related to P0740
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Automatic gearbox (torque converter and CVT): the most serious faults by engine and car
- Critical severityFrequency: CommonMultitronicWear of the variator chain and conesYes: the variator uses a chain of more than 1,000 links between two pairs of cones that wears with mileage, especially if the oil is not changed regularly. Gebrauchtwagenberater ties the gearbox's reputation to "numerous total failures"; Schaeffler/LuK sells a kit to repair the chain.
- Critical severityFrequency: Common2.0 CDI (OM640)Costly failure of the Autotronic (CVT) automatic gearboxYes: the Autotronic continuously variable gearbox, optional on the 180 CDI and 200 CDI, is the problem cited most by owners of the 140 hp version (24 of 114 testimonies) and a fault hotspot according to the ADAC up to 2006. A German source recommends avoiding it and choosing the manual gearbox.
- High severityFrequency: CommonMultitronicControl unit (TCU) failure and limp modeYes: the multitronic control unit, especially in the 01J code (up to 2007), is one of its best-documented weak points. Overheating with oil seeping into the control unit causes fault warnings and limp mode and, if ignored, can end up damaging the gearbox itself.
- High severityFrequency: Common7G-Tronic / 9G-TronicConductor plate and speed sensor failure (limp mode)Yes: one of the most cited weak points of the 7G-Tronic (722.9) is the internal conductor plate, which integrates the turbine, output and intermediate-shaft speed sensors; if it fails it can trigger a limp mode with delayed shifts or harsh jerks, although it does not always require replacing the whole gearbox.
- High severityFrequency: CommonAudi A6 C6Wear and failures of the Multitronic automatic gearbox on front-wheel-drive versionsYes: on front-wheel-drive versions with the Multitronic (CVT) gearbox, gebrauchtwagenberater.de documents jerking when pulling away that can progress to complete failure, especially on older cars; fiches-auto.fr adds selector lock-ups and torque converter breakages. The quattro versions, with the Tiptronic gearbox, do not share this problem.Repair (garage): €1,000Appears at around 120,000 km
- High severityFrequency: CommonMINI Cooper R50Faults in the CVT automatic gearbox, the manual gearbox and the clutchAccording to the reports collected by fiches-auto.fr, the Mini R50 accumulates 22 gearbox mentions and 32 clutch mentions, and the CVT automatic variant is described as fragile and 'to be avoided'. Wikipedia confirms that the CVT and the manual gearboxes were fitted depending on the year.
Gearbox mechatronic unit: the most serious faults by engine and car
- High severityFrequency: Very frequentDSG7 DQ200Mechatronic unit failure: pressure accumulator, pump and cracked housingYes: the mechatronic unit is the DQ200's most cited weak point. Its pressure accumulator and hydraulic pump can fail because of a housing design defect, with fault warnings, limp mode or loss of drive; Volkswagen has acknowledged the problem with service actions and software updates.Repair (garage): €600–€2,200
- High severityFrequency: CommonMultitronicControl unit (TCU) failure and limp modeYes: the multitronic control unit, especially in the 01J code (up to 2007), is one of its best-documented weak points. Overheating with oil seeping into the control unit causes fault warnings and limp mode and, if ignored, can end up damaging the gearbox itself.
- High severityFrequency: Common7DCTJerking, hesitation and mechatronic faults at low speedYes: several sources based on owner accounts name the 7DCT as one of the most-cited weak points of these models, with jerking and hesitation on pulling away, missing gears (sometimes reverse) and, on the most affected diesels, more than a third of the accounts mentioning gearbox faults.
- High severityFrequency: Common7G-Tronic / 9G-TronicConductor plate and speed sensor failure (limp mode)Yes: one of the most cited weak points of the 7G-Tronic (722.9) is the internal conductor plate, which integrates the turbine, output and intermediate-shaft speed sensors; if it fails it can trigger a limp mode with delayed shifts or harsh jerks, although it does not always require replacing the whole gearbox.
- High severityFrequency: CommonAudi Q5 IAudi Q5 S tronic gearbox faults: jerking, vibrations and mechatronicsThe S tronic gearbox and the transmission account for 65 and 48 testimonies out of 322 on fiches-auto.fr, with jerking, vibrations and gear selection faults; there are cases of mechatronic unit replacement at 105,000 km. No official campaign found.Appears at around 48,000 km
- High severityFrequency: OccasionalMazda CX-60Transmission control module (TCM) software: the engine and electric motor clutch may not re-engage after brakingYes: campaign AR043A corrects a software fault in the transmission control module (TCM) which, after braking, can stop the clutch between the engine and the electric motor from re-engaging; the car may not respond to the accelerator. It is fixed by reprogramming the module at an authorised workshop.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)Yes, on the first units: Hyundai and Kia recalled 2016–2018 Ioniq and Niro hybrids and plug-in hybrids because the main relay that connects the high-voltage battery could come loose, overheat and, in the worst case, cause a fire.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireYes, this is the most documented hybrid system fault: the hydraulic actuator that engages the combustion engine with the hybrid assembly has had two recalls (2018 for a leak on the Niro and 2025 for moisture in its electronic board on the Niro, Ceed and XCeed PHEV), with a risk of short circuit and fire.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
What does the torque converter clutch do?
It connects the engine to the gearbox input at cruising speed to avoid slip and save fuel. When the lock-up fails, the converter keeps slipping and consumption rises, according to AutoDTCs.[1][2]
What is the difference between P0740 and P0741?
P0740 is a fault in the clutch solenoid circuit (open or short-circuited, or a commanded lock that does not happen); P0741 is the circuit performance code and has its own page.[1]
What should I check first with a P0740?
The gearbox oil and the accompanying codes, and then the wiring and the solenoid resistance. AutoDTCs warns that the oil must be corrected before blaming the electrical parts.[1][2]
Can I keep driving with P0740?
AutoDTCs rates it as moderate and accepts short-term driving, but warns that consumption rises and the gearbox works hotter; Rerev does not recommend continuing to drive with the code.[1][3]
Will I pass the MOT with code P0740?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[4]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P0740 - Torque Converter Clutch Circuit/OpenAutoDTCs · Technical documentation · consulted 31 October 2026
- P0740 - Mal funcionamiento del circuito del embrague del convertidor de parCódigosDTC · Technical documentation · consulted 31 October 2026 · in Spanish
- P0740 OBD2 codeRerev · Technical documentation · consulted 31 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish