TransmissionGeneric OBD-II codeUrgency: As soon as possible
Code P0700: transmission control system fault (MIL request)
P0700 means: transmission control system (request to turn on the malfunction indicator lamp, MIL).[1][2][3] P0700 is a "summary" code: the transmission control unit (TCM) has detected a fault of its own and tells the engine ECU to turn on the warning light. AutoDTCs describes it as a "gateway" code and Carista as a wrapper, and both agree that on its own it says nothing about the nature of the fault. The name of the standard varies by source: "Transmission Control System (MIL Request)" at AutoDTCs and "Transmission Control System Malfunction" at Mechanic Base and TaT.[1][2][3][4][5]
What code P0700 means
P0700 is a "summary" code: the transmission control unit (TCM) has detected a fault of its own and tells the engine ECU to turn on the warning light. AutoDTCs describes it as a "gateway" code and Carista as a wrapper, and both agree that on its own it says nothing about the nature of the fault. The name of the standard varies by source: "Transmission Control System (MIL Request)" at AutoDTCs and "Transmission Control System Malfunction" at Mechanic Base and TaT.[1][2][3][4][5]
The actual fault is stored in the transmission control unit itself, not in the engine ECU. So, to find out what is going on, you need to read the codes in that control unit (normally P07xx codes for solenoids, sensors, gear ratios or clutches) with a diagnostic tool that can access the transmission module, and deal with that specific code first.[1][2][3][5]
Autodoc Club (UK version) presents it as an automatic gearbox problem. It is a generic OBD-II code (it starts with P0), so it means the same on any make.[6][7]
Original definition (SAE J2012): Transmission Control System (MIL Request)[1][2][3]
Causes of P0700
From most to least likely, according to the sources.
- 1Failure of a transmission solenoid (shift, pressure or torque converter lock-up). AutoDTCs names it as the most common underlying cause, and Mechanic Base and Autodoc Club (UK version) put it first.[3][4][6]
- 2Low level or degraded or contaminated automatic transmission fluid (ATF), or an oil leak, which affect hydraulic pressure and the operation of solenoids and clutches.[1][2][3][4][6]
- 3Dirty or faulty valve body or transmission valves.[1][4][6]
- 4Damaged, open or short-circuited wiring in the transmission control unit or the valve body harness.[1][3][4][6]
- 5Faulty transmission control unit (TCM), for example from a damaged circuit board or corrosion.[1][4][6]
- 6Faulty transmission position (range) sensor, which reports the lever position incorrectly.[3]
- 7CAN bus communication fault between the transmission control unit and the engine ECU, which is usually accompanied by U codes.[2][3]
- 8Internal mechanical faults in the gearbox.[3][4]
- 9An engine ECU problem causing false diagnoses, which is uncommon.[1]
Symptoms
- Engine warning light on.[1][2][3][4]Engine warning light: faults that cause it
- Gearbox warning light or message on the instrument cluster.[3]Gearbox warning: faults that cause it
- Gearbox limp mode, with limited gears: according to Carista, the gearbox usually stays in 3rd or 4th.[2][3][4][6]Limp mode: faults that cause it
- Delay when engaging a gear (D or reverse) or refusal to change gear, with harsh or late shifts.[1][2][3][4]Gears will not engage: faults that cause it
- The engine may suddenly stall, especially when stopping if the gearbox does not drop back to first.[1][3]Engine stalls: faults that cause it
- Slipping gearbox and high engine revs relative to road speed.[3][4]
- Noises from the gearbox.[6]Gearbox noise: faults that cause it
- Oily, red or brown fluid stains under the car, if there is a gearbox oil leak.[6]
- Worse fuel consumption.[6]Uses more fuel: faults that cause it
How to diagnose P0700
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the codes in the transmission control unit itself with a diagnostic tool that can access that module, not just the engine ECU: P0700 is a summary and the real information is there. Deal with the specific code that appears first.[1][2][3]
- 2Check the level and condition of the gearbox oil (on cars that have a dipstick). If it is contaminated, it is changed or the circuit is cleaned.[1][2][3][4]
- 3Review the freeze-frame data (engine load, revs and throttle position) at the moment of the fault.[4]
- 4Inspect the external wiring and connectors of the gearbox and of the valve body harness, and clean the electrical contacts.[1][3][6]
- 5Compare the gearbox input and output speeds on level ground (a workshop test).[4]
- 6Test the solenoids with a multimeter.[6]
- 7Clear the code to rule out a false error and check whether it returns. Replace solenoids or the transmission control unit only if the tests confirm it, and leave the diagnosis to a garage if in doubt.[1][4][6]
Can I keep driving with P0700?
As soon as possible
The sources agree that it is serious. Autodoc Club says it is not safe and must be resolved immediately, because of the safety risk and possible engine damage, and its UK version recommends avoiding driving until it is repaired. Mechanic Base classes it as serious and advises you to stop driving as soon as it is safe to do so, because continuing to strain the car can permanently damage the gearbox. Carista and AutoDTCs give it high severity; AutoDTCs qualifies that, in limp mode, you should only drive to the garage, and that the car must not be towed with the code active. The prudent course is not to carry on using the car as normal and to take it to a garage as soon as possible.[1][2][3][4][6]
Documented faults related to P0700
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.
Control units and comfort electronics (BSI, SAM...): the most serious faults by engine and car
- High severityFrequency: CommonPeugeot 408Electronic faults with the doors, boot and screen (suspected BSI control unit)In 2025 Peugeot recalled around 60,000 2023-2024 Peugeot 308 and 408 cars (code MUV) over a software fault in the door control unit that can cause unintended opening or closing and disable the anti-trap protection on the windows; 408 owners also describe a power boot lid that will not open or close and a screen that goes black.
- High severityFrequency: CommonRenault Laguna IIMultiplex electrical system and hands-free card faultsThe Laguna II had a reputation problem because of faults in its multiplexed electrical network: the hands-free card, the card reader and the ABS, ESP and handbrake warning lights came on erratically, especially in the early years of production (2001-2003).
- Critical severityFrequency: OccasionalMazda MX-5 IVDC/DC converter control unit fault with risk of short circuit and fireA 2018 Safety Gate alert covers MX-5 ND models built between August 2014 and April 2017: the DC converter control unit could fail, cause a short circuit and damage the converter, with a risk of fire. It is a precautionary recall; check the chassis number at the official service centre.
- Medium severityFrequency: Very frequentFiat StiloElectrical and electronic faults in the multiplex systemThe Stilo has had a reputation for widespread electrical faults since its launch: poor contacts in the multiplex wiring, an instrument cluster that switches off and sensors that disconnect, sometimes while the car is running.
P0700 by make
Documented faults that can trigger P0700 in each make's engines and cars.
Frequently asked questions
What does code P0700 actually mean?
That the transmission control unit has detected a fault and asked the engine ECU to turn on the warning light. It does not say which fault: according to AutoDTCs, on its own it gives no information about the nature of the fault, and TaT points out that further diagnosis is needed using the gearbox's own codes.[2][3][5]
Why does my OBD reader only show P0700?
Because P0700 is a summary code: what the reader shows is the warning from the transmission control unit, while the specific fault is in the codes that control unit stores. Carista and AutoDTCs insist that you need to read those codes with a tool that can access the transmission module.[2][3]
Can I drive with code P0700?
The sources advise against it: Autodoc Club says it is not safe and must be resolved immediately, and Mechanic Base says you should stop driving as soon as you can to avoid permanently damaging the gearbox. AutoDTCs qualifies that in limp mode you should only drive to the garage, and that the car must not be towed with the code active.[1][3][4][6]
What is the most common cause of P0700?
According to AutoDTCs, a failed transmission solenoid; Mechanic Base and Autodoc Club (UK version) also put it first. But it is best to start with the cheapest check: the level and condition of the gearbox oil, which also appears among the causes in all the sources that cover it.[1][2][3][4][6]
Does P0700 mean the same on all makes?
The definition does: it is a generic OBD-II code, and those starting with P0 are the same for all manufacturers. What changes is the specific code stored by the transmission control unit and how it is diagnosed on each model.[5][7]
Will I pass the MOT with code P0700?
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.[8]
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.
- Código de avería P0700Autodoc Club · Technical documentation · consulted 4 October 2026 · in Spanish
- P0700 OBD-II codeCarista · Technical documentation · consulted 4 October 2026
- P0700 - Transmission Control System (MIL Request)AutoDTCs · Technical documentation · consulted 4 October 2026
- P0700 Code - Transmission Control System MalfunctionMechanic Base · Technical documentation · consulted 4 October 2026
- P0700 - Transmission Control System MalfunctionThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- OBD2 Code P0700: Transmission Control System MalfunctionAutodoc Club · Technical documentation · consulted 4 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 4 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