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The Multec HSFI 2.X – A regular customer at ACtronics

By autotech-nath on March 8, 2021

“Multec? Aren’t they those ECUs (Engine Control Units) that are commonly used in Vauxhalls?”

We’re not sure if it’s a good or a bad sign, but almost every car connoisseur we speak to, knows that many Vauxhalls are equipped with a Multec ECU. Why do so many people know the name Multec? Are these ECUs really that bad? Multecs are indeed malfunctioning a lot, but this is due to several causes. It is short-sighted to put the blame entirely on the ECU itself.

Lesson 1 – when using car-electronics, always ensure the utmost protection against moisture, temperature fluctuations and vibration. Maybe Vauxhall is a little at fault in this matter – mounting an ECU right on top of the inlet manifold simply doesn’t provide the best possible environment.

What’s causing the main malfunctions?

So, the ECU is operating in a hazardous environment full of vibrations and big differences in temperature. What could possibly go wrong? Several connections on the PCB (Printed Circuit Board) tend to tear or break and it’s no surprise for us to find these defects in every Multec we get hold of. So, it actually doesn’t matter which faults we find inside the ECUs, we always check all connections directly after every diagnosis. It’s really rare to have all connections on the PCB in perfect order. Almost every Multec will therefore continue to undergo our full remanufacturing process.

It’s probably no surprise that all these defects are causing so much trouble. The complaints we find on incoming Multec ECUs are also diverse. Below, we’ve made a short list of the most common complaints:

• Car doesn’t start, fuel pump isn’t activated • Car doesn’t start, no injection
• Ignition fails on one or more cylinders
• Fluctuating RPM at idle

• Absolutely no throttle response • Faults in EGR
• No communication to CAN
• Cooling fan isn’t activated

Remanufacturing: The process

We can’t stress enough that ACtronics doesn’t repair defects, but remanufactures products. We know for a fact that these ECU’s are highly sensitive and we want to be absolutely sure a remanufactured ECU will have the quality equal to, or better than, OE (Original Equipment). We therefore not only repair all the complaints we encounter, but we also put each ECU through the complete remanufacturing process.

In this process, the protective gel will first be removed professionally. Once all components are completely unprotected, we can begin with the removal of all existing bonding wires. This is a very delicate process, but this isn’t an issue thanks to our many years of experience. Once this second step is completed, all new bonding wires will be attached to the PCB using highly sophisticated equipment. The method we use is called ‘ultrasonic bonding’. The equipment is fully programmed and set up by our engineers and because of this we can also perform a pull test on the freshly installed bonding wires. This way we know for sure every new attachment is strong enough to withstand vibrations and fluctuations in temperatures. The newly made connections are even stronger than the original ones.

Once the bonding process is complete, it is time for the final test. This test is necessary to establish if all the functions are working properly. Our testing facility also gives us the ability to perform an endurance test, in which the temperature actually rises in the ECU. You can really feel the ECU getting hot while performing this test. After this testing period, a special high specification gel will be applied in order to properly protect the PCB. Finally, we will close the ECU with a new (self-developed) cap.

If the ECU still isn’t working properly after this entire process is complete, we will proceed using much more specific methods. There are many possibilities in the field of diagnosing and solving problems.

To find out more, visit, or email your query to


The Multec HSFI ECUs are also used in cars with diesel engines. There is one malfunction that’s really standing out in these particular cases: Fault code P0251 (Injection Pump Fuel Metering Control “A” Malfunction). If you ever experience this fault code on a Multec ECU that controls a diesel engine, please send in both the ECU and EDU (Engine Diesel Unit). In most cases, it’s the EDU that’s causing this fault code, not the ECU itself.



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Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
Aftermarket Media Solutions Ltd, The Joiners Shop, Historic Dockyard Chatham, Kent ME4 4TZ
T: 01634 816 165
Company no. 09625886
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