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BMW 1 Series High-Pressure Fuel warning


At Fergies, we work with any problems on BMW, big or small. Our goal is to get every single client back on the road quickly and as safely as possible. We are not just mechanics; we are problem solvers.

When a recent client of ours arrived at the garage with his BMW 1 series and said to us, “My car is cutting out, and I don’t understand why”, we were prepared to use our experience and knowledge to solve this problem.

The client told us that he had already replaced some parts, but the car still wasn’t working.


The client told our BMW specialist technician that he had noticed when driving the vehicle that after about 20-30 minutes, the BMW 1 Series would lose power and then completely cut out. With no warning, this was a dangerous problem that needed immediate attention.

The BMW would restart, but only once the car had completely cooled down.

With no way of knowing when or why this was happening, the client knew he had to get the issue sorted as soon as possible. The client made the wise decision to bring his BMW 1 series to Fergies so he could get back on the road quickly and safely.

BMW 1 Series High-Pressure Fuel warning


Once the vehicle was under our care, the client advised that they had already replaced some parts on the BMW 1 series, but the problem of cutting out was still evident. The client had replaced the following:

  • The In-tank Fuel Pump
  • The Fuel Rail Pressure Sensor
  • The High-Pressure Fuel Pump

This had already cost the client over £1,500, and the car was still not working. 


At Fergies, we don’t believe in guessing or swapping out parts in the hope of getting lucky and resolving the issue – this can prove expensive and time-consuming whilst still not getting to the root of the problem. That’s why we use our proven unique 15 steps diagnostic process to track down the fault – only replacing or repairing what we need to.

Having access to official BMW guidelines means creating a rigorous test plan to evaluate the car thoroughly. We always get to the root cause of the issue fast.

We carried out a complete evaluation using an oscilloscope, retrieved error codes and inspected serial data. The error code retrieved was:

  • 11A002 – High-Pressure Fuel, Plausibility, Pressure too low

Now that we knew this was an intermittent fault, we needed serial data. We needed to road test the BMW to work out when it cut out. The road test also allows us to monitor live data from the car’s engine management computer.

With the car running, we completed the initial checks to the low-pressure fuel system. Our checks confirmed that the low fuel pressure pump and all the associated wiring was working with no faults or concerns and were in good condition.

We confirmed that whilst the vehicle was running as it should, the desired and actual fuel pressure were within the manufacturer recommended guidelines and, therefore, nothing at fault.

However, at this moment, the power went after 20-30 minutes, and we experienced what the client had expressed to us in front of our own eyes. But with our comprehensive understanding of the serial data, we were able to capture all information we needed to diagnose the fault.


Our serial data analysis found that when the BMW started to fault, the 12v supply to the fuel pump was lost. It had been present up until this point, so we knew that we had to investigate deeper. The 12v supply was fully restored to the fuel pump when the car cooled down, meaning this was a heat issue.

Our expert technician found the 12v feed for the fuel pump and noticed that it came from a relay by following the official BMW documentation. After stripping it back to access the relay, we tested it to check if this was the issue.

We found that the relay was breaking down and faulting when warm. This explains why the issue only occurred after a prolonged driving period.


As a BMW specialist garage, we have access to genuine BMW parts, technical information and data, which means we are expertly placed on maintaining your vehicles integrity.

Our specialist BMW technician was able to diagnose and replace the faulty relay immediately. After clearing the error codes and taking the BMW 1 series on an extended road test, we confirmed that the issues had been fully resolved. When the engine warmed, the car was driving perfectly.

At Fergies, we pride ourselves on achieving a ‘first time fix’ – we know that our customers’ time is precious. We understand that no one wants to keep returning to a garage time and time again to resolve an issue with their BMW. At Fergies, we get it.

No unnecessary parts were replaced—no unnecessary return visits. Safe motoring. Quality workmanship. Value for money.

At Fergies, we use an evaluation process that allows us to find uncommon, less obvious faults within your BMW. 

Contact us today on 01635 778002, and we can get your vehicle in front of our BMW experts as soon as possible.

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