The Kia Soul hybrid and PHEV suffer more frequently from specific technical problems than traditional petrol models. Battery failures, malfunctioning stop-start systems and emission-related complaints regularly crop up among owners of newer models. These problems seem partly related to the more complex drivetrain in the hybrid and plug-in hybrid versions. What problems might you encounter and how do you recognise them?
Battery problems mainly affect hybrid and plug-in hybrid models
A common problem with the Kia Soul hybrid and PHEV is the 12V battery running flat. This battery supports the electronics and starting the vehicle, even when the main battery is full. Owners report that the 12V battery can discharge without warning, preventing the vehicle from starting. This occurs more often in hybrid models than in regular petrol versions.
The ICCU (a module that controls battery charging) is another vulnerable component. This integrated charging control unit (Integrated Charging Control Unit) manages charging of the battery and can fail. When the ICCU fails, the charging system no longer works correctly. This can then cause problems with starting the car. Many owners report that this issue is resolved under Kia’s seven-year or 100,000-mile warranty, but it can still be very inconvenient. Kia Soul owners are well advised to check the battery status every month and take action immediately if they notice slow starting.
The main battery in PHEV variants also has its own specific challenges. The charging speed is relatively slow, with 30 minutes needed to go from 0 to 80 per cent on fast charge, which only delivers around 100 miles (about 160 kilometres) of range. Temperature and driving style have a major impact on range. In cold weather and with hard acceleration, range can drop by 20 to 30 per cent.
Stop-start system fails regularly
The stop-start system, which automatically switches off the engine when stationary to save fuel, is not always reliable in the Kia Soul hybrid. Owners report that the system sometimes refuses to activate or fails to restart after a stop. This can lead to unexpected situations in traffic.
The causes vary:
- Weak 12V battery that blocks the system as a safety measure
- Faulty sensors sending incorrect information about engine temperature or battery status
- Software issues in the control unit of the stop-start system
- Wear of the starter motor due to intensive use in urban traffic
Models from 2018 also suffer from cruise control problems, which appear to be related to the hybrid system. The system can suddenly accelerate or decelerate without any input from the driver. This is dangerous and should be reported to the dealer immediately. Always test the cruise control system in safe conditions before using it in heavy traffic.
Emission-related complaints in newer models
Newer Kia Soul hybrid models struggle with emission-related faults. The exhaust systems can overheat, leading to damage. This problem mainly occurs on short trips where the hybrid system frequently switches between electric driving and the combustion engine. The catalytic converter then fails to reach its optimal operating temperature, which can result in incomplete combustion and higher emissions.
Engine complaints are also linked to the hybrid system. Knocking sounds from the engine and ticking noises occur, sometimes along with oil leaks. The cause often lies in the complex interaction between the electric motor and the combustion engine. When switching between both drive types, additional load is placed on engine components, which accelerates wear.
When buying, always check whether there have been any recalls. A recall has been issued for the 2022 model. Make sure this has been carried out before you complete the purchase. A test drive giving particular attention to engine noises and suspension is essential to uncover hidden problems.
Reliability varies by model year
Although the Kia Soul hybrid scores from average to good in reliability surveys, there are differences between model years. Early versions more often suffer from transmission problems such as clicking when steering and suspension clunking. Newer models from 2020 onwards show improvements in these systems, but at the same time introduce new challenges with the electrified drivetrain.
Depreciation remains favourable, with only 21 per cent loss of value after five years. This makes the Soul attractive for owners who want to drive the same car for a long time. Fuel efficiency is 30 per cent better than comparable models, which partly offsets the higher maintenance costs for hybrid components.
Routine maintenance such as oil changes and tyre rotation remains affordable. For specific hybrid components such as the ICCU or main battery, the warranty is often sufficient. Follow the Kia maintenance schedule strictly to avoid expensive repairs. Regularly check fluid levels and have the brakes inspected early, as hybrids recover braking energy more often and this can lead to uneven wear.
‘ “These problems do not seem directly related to the hybrid powertrain, but do occur more frequently in electrified models due to the more complex electrical architecture.” ’
Infotainment and electronics suffer from faults
The head unit of the infotainment system restarts at random while driving. iPhone connections are regularly interrupted and in severe cases the system can fail completely. These problems do not seem directly related to the hybrid powertrain, but they do occur more often in electrified models due to the more complex electrical architecture.
Sensor failures have also been reported. Parking sensors give false alerts and cameras sometimes cut out. This can lead to dangerous situations, especially when reversing or parking in tight spaces. In the event of persistent faults, a full vehicle reset can help: switch off the engine, wait a few minutes and restart the system.
Practical tips for hybrid Soul owners
If you want to prevent problems or detect them at an early stage, follow these tips. Charge PHEV variants regularly to make maximum use of the electric mode. This saves fuel and reduces the load on the combustion engine. While charging, keep the charging cable and charging port clean to prevent contact problems.
When buying, opt for recent models with the long-range battery option, which offer up to 172 miles of range. Avoid early model years with known transmission issues unless you have documentation of repairs carried out under warranty. Check the full service history and ask specifically about repairs to the hybrid system, the ICCU and the 12V battery.
In daily use, keep an eye out for early warning signs. Slow starting indicates battery problems. Engine noises such as ticking or knocking require immediate inspection. Report cruise control irregularities to the dealer straight away, as these are a safety issue. Schedule monthly checks of all fluid levels and the condition of tyres and brakes.
Is the Kia Soul hybrid worth it
For economical drivers who mostly cover shorter distances, the Kia Soul hybrid offers clear benefits. The fuel savings are significant and the low depreciation makes the model financially attractive for long-term ownership. The extensive warranty covers many of the specific hybrid problems, which limits the risk.
Even so, the battery, stop-start and emission issues require extra attention. Reliability is lower than that of traditional petrol models, although newer versions show improvement. If you are prepared to follow the maintenance schedule strictly and carry out monthly checks, the problems are manageable.
On the Carnews website you will find much more information about specific car problems and maintenance advice. Owners of similar models also share their experiences. Discover more practical tips and stay up to date with developments in hybrid technology and Kia models.
Frequently asked questions
The most frequently reported technical problems with the hybrid powertrain in the Kia Soul are complaints about the 12V battery regularly discharging and defects in the ICCU (Integrated Charging Control Unit), which can cause charging and power issues. In addition, electronic faults are reported, such as infotainment and sensor problems, which can lead to systems restarting or failing. Some owners also report engine noises (knocking/ticking) and occasional oil leaks, which are sometimes linked to the hybrid powertrain. Finally, there are reports of shifting and suspension noises, although these have improved in more recent model years.
The high-voltage battery in the Kia Soul PHEV is designed for a long service life, with Kia generally offering a factory warranty of up to 7 years or around 150,000 km (depending on market and model year) on the battery. In practice, owners report few serious degradation issues in the first years, provided the car is charged regularly and properly maintained. As with all PHEVs, usable capacity slowly decreases over time, but this process is usually gradual and remains within the limits that Kia considers normal. In cases of unusually rapid degradation, this can often be assessed and, if necessary, remedied under warranty.
Yes, there are several known software and electronic problems reported with the Kia Soul hybrid and PHEV. Examples include infotainment systems that restart or freeze, loss of smartphone connections, and faults in sensors and electronic charging or battery control systems (such as the ICCU). There are also reports of cruise control that unexpectedly accelerates or decelerates, particularly in certain model years. Many of these issues are usually resolved under the Kia warranty.
In a used Kia Soul PHEV, particular attention should be paid to the high-voltage traction battery and the charging/charge control system (ICCU and on-board charger) because of known faults and possible warranty claims. The 12V battery is also maintenance-sensitive and may discharge more quickly than usual. In addition, the infotainment system and the rest of the electronics (head unit, sensors, connectivity) deserve extra checks, as faults have been reported here fairly regularly. Finally, it is wise to pay extra attention to the suspension (clunks, clicking when steering) and any early wear in transmission-related components.
There are no major, globally known recalls that apply exclusively to the Kia Soul as a hybrid or PHEV; most known issues relate to EV or petrol variants and fall under normal warranty handling. However, for electrified Kia models (including Soul-like drivetrains), there are recall actions or service campaigns for the ICCU (charging module) and 12V battery, which are sometimes carried out by the dealer as a “campaign”. Potential buyers should therefore ask a Kia dealer to check via the chassis number (VIN) whether all outstanding campaigns and recalls have been carried out. Also check whether software updates for infotainment and charging/battery management have been installed, as these often fall under service campaigns.