Potential faults on the Isuzu KB-250

Issues to be aware of

Whether it is the Single Cab or the Double Cab, one thing that cannot be disputed is that Isuzu has been making great bakkies for a very long time. It has even been noted that Isuzu perfected this when they made the Isuzu KB, built for toughness and endurance. Today we will look at the KB 250, a bakkie considered to be sensible and sturdy but not without some faults which you should be aware of.

Awareness and prevention go hand in hand to the same extent that ignorance and disaster does. At Steves Auto Clinic, leader in the field of car service and repairs in South Africa, we care about people and their vehicles. We have highly trained and skilled mechanics, ready and willing to assist you if you ever experience any of the following issues with your Isuzu KB 250.

Brake Pedal Switch

What can happen is that while you are driving, your Isuzu’s engine light may come on and the vehicle may enter a limp mode.  This is surely a concerning episode, but the cause may be less severe as you may think. At times the brake pedal switch can malfunction, what happens then is that the ECU (computer box) will send a signal to the vehicle that the vehicle is braking (even while you are driving). When your vehicle enters a limp mode, you will feel that no power is being created. Before you consider having the switch replaced, first test it or have it tested with a multimeter because it can happen that the plug going into the switch, became dislodged and pulled out. Another cause may be the build-up of carbon on the connector points. If this can be cleaned the problem may just be solved.

Auto Gearbox Problem

Some owners highlighted the issue of the gearbox that simply disengages at times, causing the engine to rev with no power to the wheels. Then, all of a sudden, the wheels will engage and that will cause a severe pull away with spinning wheels. This random engaging and disengaging of the gearbox is a serious safety risk. What if you need to step on the gas to avoid a dangerous situation, you need that extra power delivered to the wheels, but then it disengages! The cause of this to happen can be due to a worn or broken link that holds the gears. It may also be due to a problem with your vehicle’s torque converter. The cause may even be as small as a faulty gearbox speed sensor that may eradicate erratic gearbox and speedo behaviour. These are not the only possible causes; the best advice is to bring your vehicle to one of our Steves Auto Clinic branches and have your vehicle inspected by one of our electricians and have it repaired as soon as possible.

Poor Fuel Consumption

The Isuzu KB 250 has a combined cycle consumption of 7,9l / 100km (12.6km/l) yet many owners raised the issue of poor consumption, averaging around 9km/l instead. What may be the cause of this? One owner, after he had his KB’s head reconditioned, found that the injectors were over-tightened. This caused distortion producing a poor spray pattern, and even though they looked fine, the distortion was only seen after having it tested. It will also be wise to have the suction control valve inspected because dirty diesel may cause this to pack up. Whichever is the case, be on the safe side and don’t let bad consumption tear a hole in your pocket. Let one of Steves Auto Clinic’s mechanics investigate your vehicle whenever you experience poor consumption, especially nowadays where fuel and diesel prices are at their all-time high.

Hot Start Issues

What happens, especially with regards to the D-TEQ, is that the engine swings but it fails to start. If you start the engine without waiting for the engine light to go off, the engine runs but cuts out after a few seconds. Many may suggest having the fuel line inspected for any leaks or presence of air blocks because as many may know, diesel needs a lot of pressure to work properly. Doing this and bleeding the system, is surely one possible remedy. Always remember to have all the filters inspected as well. Air and other impurities (junk) in your fuel filter will kill your engine. Another possible remedy is to bypass the decoding unit on the injector pump. The decoding unit on your pump will decrypt your key when you switch the ignition to ACC. If this does not happen, your pump will switch off. Due to excessive vibration & exposure to heat, these units are prone to giving hassles. This unit may be bypassed; in doing that it may not only remedy the problem, but it may make your vehicle more susceptible to theft (no key decryption so any key that you cut will start your bakkie). Fixing it later may however cost you quite a bit of money. Steves Auto Clinic do not want to give you any advice that may harm you and your experience with your vehicle, so in the event of anyone following this advice, then this should be done on the grounds of your own will.

Other Start Issues

Some KB 250’s may display issues of starting problems whenever the vehicle’s engine is warm, but not when it is still cold. It may be so severe that it will point blank refuse to start at all whenever both the outside and engine temperatures are very warm. Mostly the engine will click but fail to engage (turn the engine). Several suggestions to remedy this, has been made. Among the suggestions are the glow plugs that should be checked. If it is not the glow plugs itself then it may possibly be the censor controlling the glow plugs. It may happen that the censor wire can have a chafe which causes a ground issue (bad earth) with the engine.

Some owners, who experienced the same problem, took the advice given by others owners with the same issue to heart to put a new earth cable (a new battery cable should be used for this purpose) from the battery to one of the bolts that hold the starter in place. One KB owner went through a set of glow plugs, two starters and a new battery, without any success, but after he connected the additional cable the problem was solved instantly and the engine started under all conditions. If you consider having this done, then let it be done by a professional to ensure that you do not do something that may cause additional damage.


The calipers – it is said – have to be replaced during every service. Many Isuzu KB owners highlighted the point that the calipers were prone to failure. Apparently the brake calipers were also problematic in previous models so ensure to have these inspected by one of our mechanics.

The Isuzu KB 250 is otherwise as reliable as they come. The 250 engines are of the good type and they are tough as nails. Countless of owners can testify of more than 500 000 trouble-free kilometres on the clock. Compared to other bakkies on the market, being driven under the same conditions, the Isuzu KB 250 has proven itself to outlast its competitors. There is even one warning doing the rounds regarding the D-TEQ – they are prone to cause adictalitus (a condition causing the owner of the D-TEQ to become addicted to and obsessed with the D-TEQ)!

If ever your ‘tough as nails’ Isuzu show any of the issues highlighted above, then know what to do: bring it to your nearest Steves Auto Clinic for a thorough check-up by one of our well-trained and skilled mechanics. As leader in the automotive repair and service industry, we care about you and your vehicle’s well-being. Read more on possible power upgrades for the Isuzu KB D-TEQ.

Within the above article, potential problems, causes and fixes have been identified as founded on the experience of vehicle owners and repairers, online sources such as discussion blogs, technical service bulletins and SAC experience. This information is provided solely for reference purposes. SAC strictly instruct readers that only properly qualified individuals should carry out repairs and/or modifications on your vehicles. It should also be made clear that the number of times an item is identified within this discussion should by no way be seen as an indicator of a model’s reliability or the frequency with which they may occur. Two of the exact same vehicles, owned by tow entirely different owners, driven in entirely different ways and on different terrains, and looked after in their own unique ways, will each behave differently. As mentioned, this information is provided solely for reference purposes but we hope – in the process of doing so – to empower you with relevant information which may enable you to make informative decisions whenever you experience any of the mentioned setbacks.