Electrical system and control unitsGeneric OBD-II codeUrgency: Garage soon
Code P0607: ECU performance fault
P0607 means: control module: performance problem of the module itself.[1][2] The ECU monitors its own operation and that of other modules on the network. If it detects an internal fault, such as damaged memory, a processor that is not behaving properly or a voltage drop, it logs P0607 (Control Module Performance).[1][2]
What code P0607 means
The ECU monitors its own operation and that of other modules on the network. If it detects an internal fault, such as damaged memory, a processor that is not behaving properly or a voltage drop, it logs P0607 (Control Module Performance).[1][2]
It is a generic OBD-II code and, according to the sources, it can range from a one-off glitch to a problem with the ECU or its power supply.[1][2]
Original definition (SAE J2012): Control Module Performance[1][2]
Causes of P0607
From most to least likely, according to the sources.
- 1Weak battery, poor terminals or an unstable alternator: low or fluctuating voltage upsets the ECU's internal checks.[1][2]
- 2Corrupt or outdated programming, for example after a failed update or a battery that went flat during reprogramming.[1][2]
- 3Poor earths and corroded or loose connectors at the ECU.[1][2]
- 4Water or moisture in the ECU, or damage from a knock or a poor repair.[1][2]
- 5Physical internal fault in the ECU (fatigue from thermal cycling, faulty electronic components).[1][2]
- 6Problems in the communication network (CAN bus).[2]
Symptoms
- Engine warning light on; depending on the fault it may not come on.[1][2]Engine warning light: faults that cause it
- Limp mode with limited power and speed.[2]Limp mode: faults that cause it
- Inability to start or intermittent starting.[1][2]Hard to start: faults that cause it
- Stalling at idle or when pulling away with little throttle.[1][2]Engine stalls: faults that cause it
- Weak throttle response and little power.[1][2]Less power: faults that cause it
How to diagnose P0607
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the code and the freeze-frame data, and note the other stored codes: the context is a big help.[1][2]
- 2Clear the codes, switch off the ignition for about 30 seconds and try to start. If the code does not return, it may have been a one-off glitch.[1]
- 3Test the battery (over 12.4 V at rest and a load test) and check that the alternator delivers a stable voltage of about 13.5 to 14.5 V.[1][2]
- 4Check the wiring harness, connectors and earths of the ECU, looking for corrosion, damage or loose pins, wiggling the connectors while watching live data.[1][2]
- 5Look for technical bulletins for your make and model: according to one source, many P0607 cases are software faults with an official fix.[2]
- 6Only if everything above is fine should the ECU or its programming be suspected.[1][2]
Can I keep driving with P0607?
Garage soon
The sources indicate it may have no symptoms or may go as far as preventing starting, causing stalling or triggering limp mode. As the effect is unpredictable, it should be diagnosed soon.[1][2]
Documented faults related to P0607
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
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.
12 V battery: the most serious faults by engine and car
- Medium severityFrequency: Common2.0 and 2.5 HybridThe 12 V battery goes flat if the car sits unused for several daysYes, it is a common complaint: the 12 V battery can go flat after just a few days without using the car, because of the standby drain from the electronics (multimedia, telematics, keyless entry). With the 12 V battery very low, the hybrid system can lock itself into a safe mode.
- Medium severityFrequency: OccasionalE-Tech Híbrido12 V battery going flat or needing early replacementSeveral Clio, Arkana and Austral owners with the E-Tech engine document premature replacement of the 12 V auxiliary battery, in one case twice in the first year. It is not the most widespread fault of the system, but it appears repeatedly across different models.
- Medium severityFrequency: Occasional1.5 Hybrid12 V battery going flat while parkedYes: on the hybrid Yaris and Yaris Cross, the 12 V battery can go flat within a few days while parked because of the residual draw of modules such as eCall or keyless entry. It is fixed with a software update or, if the battery is already damaged, by replacing it.
- Low severityFrequency: OccasionalHonda e:HEV / i-MMD12 V battery going flat and hybrid system failing to startIf the car stands unused for a long time, the 12 V auxiliary battery can go flat and the hybrid system does not activate ("Ready" does not appear) even though the traction battery is charged. It is fixed by charging or replacing the battery.Repair (garage): €120–€250
- High severityFrequency: CommonHyundai Ioniq 5Faulty ICCU: 12 V battery drain and loss of drive powerThe Integrated Charging Control Unit (ICCU) can fail on the Ioniq 5: it drains the 12 V battery, may refuse to charge and, in the most serious cases, cause the car to lose power or not go into drive mode. Hyundai has replaced this part and updated its software on units built between January and February 2023.
- High severityFrequency: OccasionalBMW Serie 6 E63/E64Battery drain and loose positive cableThe battery and alternator are frequently cited by Fiches-auto, and there is a recall for the battery's positive cable, which can work loose.
Alternator and starter motor: the most serious faults by engine and car
- High severityFrequency: Occasional2.2 JTDm Multijet IIAlternator cable touching the exhaust gas recirculation pipe (fire risk)An Alfa Romeo campaign covers diesel Stelvio built between 18 January 2017 and 18 September 2018: an alternator cable may rub against the exhaust gas recirculation pipe and cause a short circuit, with a fire risk in the worst case.
- Medium severityFrequency: Occasional1.7 CDTIPremature alternator wearThe Hitachi-brand alternator fitted at the factory to the 1.7 CDTI tends to wear out sooner than expected, according to a German buying guide on the Opel Astra H, with typical replacements at around 140,000 km; there are similar accounts on the Opel Meriva with this engine.
- Critical severityFrequency: OccasionalAlfa Romeo JuniorRisk of electric arcing at the 48 V starter-generator terminal on the hybrid JuniorYes: a March 2026 Safety Gate alert (campaign F60F) covers Junior MHEVs built between 27 November 2023 and 18 December 2025. The clearance between the particulate filter pipe and the 48 V starter-generator terminal cover is under 10 mm and, in damp conditions, there could be electric arcing and fire.
- Critical severityFrequency: OccasionalBMW Serie 3 G202025 campaign for corrosion of the starter motor relay (risk of fire)Yes: in September 2025 BMW recalled, among other models, the 2019 to 2021 330i (G20) because the starter motor relay can corrode, overheat and cause a short circuit with a risk of fire even when the car is parked.
Frequently asked questions
What does P0607 mean?
That the ECU has detected a problem in its own operation. It can range from low supply voltage to a software fault or a fault in the electronics themselves.[1][2]
Is P0607 serious?
It depends. It may be limited to a warning light or may cause stalling, failure to start and limp mode.[1][2]
Does it improve if I replace the battery?
Sometimes. One source points out that many P0607 cases disappear once the battery is fixed, which is why it is worth testing it before the ECU.[2]
Can a software update fix it?
Yes, in some cases: one source says many P0607 cases are known software faults with an official fix from the manufacturer.[2]
Will I pass the MOT with code P0607?
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.[3]
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.
- P0607 – Control module -performance problemTroubleCodes.net · Technical documentation · consulted 29 October 2026
- P0607: Control Module Performance - Symptoms & Fixescarfaultcodes.co.uk · Technical documentation · consulted 29 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