‘Check hybrid system’ or hybrid system malfunction: what the warning means and what to do

Do you see a warning about the hybrid system or the electrical system in your hybrid, plug-in hybrid or electric car? Then the car has found a fault in the control system or in a part of the electric drive. In this article you can read when you should stop, when you can drive on carefully to a garage and why the small 12-volt battery often plays a part.

By the team at Autobedrijf Willemsbrug, RDW-approved APK (MOT) test station since 1979 · Updated 8 November 2026

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The short answer

A warning such as ‘Check hybrid system’ or ‘Hybrid system malfunction’ means that the car has found a fault in the control system or in a part of the hybrid or electric drive. If the car drives normally, no red light is on and READY (the car is ready to drive) is lit, you can drive on carefully home or to a garage and have the fault read out. If a red light is on, READY flashes, READY goes out or the car will not go into READY, stop as soon as it is safe and have roadside assistance bring the car in. A fault does not automatically mean that the high-voltage battery pack is broken: a weak 12-volt battery can also be the cause.

What does the ‘Check hybrid system’ warning mean?

The warning means that the computer that controls the hybrid drive has stored a fault. That fault can be in the control system itself or in one of the parts connected to it. In the owner’s manual for its hybrid and plug-in hybrid models, Kia writes that the service warning light comes on when there is a fault in the hybrid control system or its components.

The text on the screen differs by make, model and language setting. You may see ‘Check hybrid system’, ‘Hybrid system malfunction’, the Dutch ‘Controleer hybride systeem’ or only a service light. A fully electric car shows a similar warning about the electrical system for this kind of fault. Your owner’s manual tells you which name and symbol your car uses.

The READY light matters too. According to Kia, if READY is lit, the car can be driven normally. If READY is off, normal driving is not possible or a fault has occurred. If READY flashes, the car is running in an emergency mode. So with every warning, also look at READY.

Does the light come on briefly when you switch the car on and then go out? That is the bulb check and nothing is wrong. Only if it stays on or comes on while you drive is there a fault. You can find an overview of all lights by colour in our guide to dashboard warning lights.

Should you stop or can you keep driving?

That depends on the colour of the light and on READY. The ANWB, the Dutch motoring organisation, uses a clear rule: with a yellow or orange light you can keep driving for a while and should drive to a garage when you can. With a red light you pull over safely straight away. If in doubt, take the most cautious option.

What you notice What it may mean Keep driving?
A yellow or orange hybrid system warning, READY is lit, the car drives normally A fault in the control system or in a part has been stored Yes, drive on carefully home or to a garage. Have the fault read out soon
The car clearly has less power The car limits itself to protect parts Only drive carefully to a safe place or a nearby garage. Do not take the motorway
READY flashes or goes out while driving According to Kia, the car is in an emergency mode or normal driving is not possible No. Stop as soon as it is safe and call roadside assistance
The car will not go into READY Often a weak or flat 12-volt battery, sometimes another fault No. Do not keep trying and call roadside assistance
A red light, for example brakes or cooling, next to the warning A fault that directly affects safety or the car’s systems No. Pull over safely straight away and call roadside assistance
Smoke, a burning smell or sparks Possibly a serious electrical fault No. Stop, get everyone out of the car and call 112

This is an indication. The real cause only becomes clear after reading out the fault. Sources: ANWB, Waarschuwingslampjes op het dashboard, and the Kia owner’s manual (hybrid and plug-in hybrid, 2023).

Kia mentions another light you should take seriously: if the red and the yellow light of the regenerative braking system come on together, the brakes are not working properly. The brake pedal may feel heavier and the stopping distance may be longer. Regenerative braking is braking where the electric motor slows the car down and charges the battery. For a red brake light, the ANWB writes that driving on can be dangerous. Our advice is therefore: stop and have the car brought in.

Is the car not safe to drive any further? Have roadside assistance, the ANWB Wegenwacht (the ANWB’s roadside patrol) or a recovery service bring the car to us. When you call, say that it is a hybrid or electric car. Outside our opening hours this is possible at your own risk. The car is parked outside our garage and the key goes through our letterbox. After smoke, a burning smell or a collision, do not leave a hybrid or electric car unattended outside our garage. If your car cannot be driven, we put it into our schedule as soon as possible.

Why will my hybrid or electric car not go into READY?

A common cause is a flat or weak 12-volt battery, even when the battery pack is full. The 12-volt battery is the small battery that powers the computers, the locks and the screens and that switches on the high-voltage system. If that battery is too weak, the rest does not start up.

The ANWB writes that a flat starter battery in a hybrid is fairly common after two to three weeks without driving, especially if the car is used little. If the voltage is too low, the READY signal is not released and the car effectively does nothing. According to the ANWB, a car that will not start usually does not mean that the battery pack is broken. Replacing the 12-volt battery often solves the problem.

A weak 12-volt battery can also cause other odd warnings, such as a warning about the charging system or the electrical system. That is why, with a hybrid system warning, we also test the 12-volt battery before any part is replaced. You can read more about causes, jump starting and prevention in our article about a flat 12-volt battery in an electric or hybrid car.

In its owner’s manual, Kia also names other reasons why the hybrid system can stop: an empty battery pack, an empty 12-volt battery or an empty fuel tank. So with a hybrid, also check that there is enough fuel in the tank.

What can you do yourself when the warning appears?

You can stop safely, restart the car and pay close attention to what you see. In its owner’s manual, Kia describes these steps for when the hybrid system stops:

  1. Slow down gradually and find a safe place to stop.
  2. Put the selector in P and switch on the hazard lights.
  3. Switch the car off and start it again, with the brake pedal pressed, as described in your car’s owner’s manual.
  4. Look at READY and the lights. Does the car go into READY, is no red light on and does it drive normally? Then drive on carefully home or to a garage. Does the car not go into READY or does a red warning stay on? Call roadside assistance.
  5. Take a photo of the screen and write down when the warning came on: when starting, when pulling away, in warm or cold weather. That helps when we look for the cause.

Do not clear the fault yourself with a cheap code reader (an OBD dongle) if the cause is not known. The light goes out, but the information the mechanic needs is gone. If the car is often left unused for long periods, take it for a proper drive regularly. The ANWB advises driving for at least twenty minutes once a week.

Keep away from the high-voltage system. Do not touch orange cables, orange connectors or parts with a high-voltage symbol, and do not open any covers. Kia’s owner’s manual says the same. After an accident, do not touch loose wires or cables. In case of fire, leave the car straight away and call 112.

How do we find the cause of a hybrid system fault?

We read out the fault with diagnostic equipment and test the 12-volt battery before any part is replaced. Our mechanics are GMTO-certified for maintenance and diagnosis on hybrid and electric cars. We do not work on the high-voltage battery pack itself.

  1. Questions: we ask what you noticed and which warning you saw. Your photo of the screen helps.
  2. Reading out: we read the fault codes and the stored conditions, such as the temperature and the speed at the moment of the fault.
  3. Testing the 12-volt battery: with a battery tester we measure whether the 12-volt battery is in good condition and whether the car charges it properly.
  4. Targeted checks: we look at what the code points to, such as the coolant of the engine or drive system, connectors, sensors or the brakes.
  5. Quote: we tell you in advance what the repair costs. We only repair with your approval.

Reading the fault codes costs a fixed amount. Call us and we tell you in advance. It is not deducted from a repair. Is the car still safe to drive? For a warning light you can walk in Monday to Friday without an appointment at Autobedrijf Willemsbrug, Boterdiep 11 in Rotterdam-IJsselmonde, and we see whether we can look at it straight away.

With a lease car, the lease company sometimes decides where the car is repaired. Do you drive a lease car? Ask your lease company first whether you may choose your own garage. If you may, you are welcome. If the car belongs to you or your company, you choose your own garage. Read more about taking a lease car to your own garage.

What do we do and not do on a hybrid or electric car?

We read out faults, test and replace the 12-volt battery and carry out maintenance around the drive system.

  • We do: read out faults with diagnostic equipment.
  • We do: test and replace the 12-volt battery, and register it with the on-board computer if the car requires that.
  • We do: check the coolant of the engine or drive system according to the manufacturer’s specification.
  • We do: brakes, tyres and air conditioning, also on hybrid and electric cars.
  • We do: maintenance according to the manufacturer’s schedule.
  • We do not: open or repair the high-voltage battery pack.
  • We do not: handle warranty claims on the battery pack. For that, you go to the dealer.

Does reading out the fault show that the battery pack needs work? For work on the battery pack, ask the dealer of your make or a specialist. You can read more about servicing a hybrid on our page about hybrid car service and repair. If you drive a fully electric car, also read which maintenance an electric car still needs.

Regular maintenance prevents many faults. During a car service we check, among other things, the brakes, the tyres, the coolant of the engine or drive system and the 12-volt battery. You get a quote in advance based on your registration number (kenteken).

Is a battery pack fault covered by the warranty?

The manufacturer decides that. The warranty conditions for the battery pack differ by make, model and year. For the warranty on the battery pack, go to the dealer.

Do you drive a Toyota hybrid? Then also read our article about Toyota hybrid maintenance and the warranty (in Dutch).

Frequently asked questions

Can I drive on the motorway with a ‘Check hybrid system’ warning?

No. We advise against it. If the car has less power, you cannot merge and accelerate properly. Use local roads and drive on carefully home or to a garage, or call roadside assistance.

What if the hybrid system warning has gone after a restart?

The fault then usually stays stored in the memory. Have the car read out anyway, especially if the warning comes back.

Is the battery pack broken when this warning appears?

No. Not automatically. The warning can also come from a sensor, a connector, the cooling system or a weak 12-volt battery. According to the ANWB, replacing the 12-volt battery often solves starting problems. Only after reading out the fault do you know what is wrong.

What does it cost when the hybrid warning light is on?

That depends on the cause. Reading the fault codes costs a fixed amount, which we tell you in advance. It is not deducted from a repair. After that we tell you in advance what the repair costs, and we only repair with your approval.

Can I come in without an appointment with a hybrid warning light?

Yes. If the car is still safe to drive, you can walk in Monday to Friday for a warning light, and we see whether we can look at it straight away. If in doubt, call +31 10 479 00 00 first.

Does this also apply to a fully electric car?

Yes. An electric car also has a 12-volt battery and a READY light or a similar message. The same rule applies: a red light or no READY means stop and call roadside assistance. We read out the fault and test the 12-volt battery.

Can I explain the problem in English?

Yes. Our team speaks Dutch and English. You can explain the warning and what you noticed in either language.

Hybrid system warning on your dashboard?

Call +31 10 479 00 00 and tell us what you see. We read out the fault, test the 12-volt battery and tell you in advance what the repair costs.

You will find us at Boterdiep 11 in Rotterdam-IJsselmonde, close to Stadion Feijenoord (De Kuip). We work by appointment. For a quick question or check you can walk in without an appointment.

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