This is an aerial off an Audi A7. The car is a bit of a special one, manufactured in 2010 it has 2 front radar sensors and a laser sensor for long range detection which is very rare for a car of its age and would with no doubt been a top of the range model when it was bought in 2010.
The vehicle came to us with a ADAS system fault, it was all down to this aerial antenna. The vehicle had various aerial antenna fitted to it controlling different things. The roof antenna (as pictured) was for GPS & navigation.
After various diagnostic tests we narrowed it down to the GPS aerial not working and then intern to the component itself which was faulty. What wasn’t apparent at first is why the ADAS system faulted because of this component failing? Although GPS is thought to be the future of automotive driving and vehicle to vehicle communication, we knew that the ADAS features on the vehicle did not rely on any information or data from the GPS as it was only being used for the satellite navigation system.
After looking through some technical data on ODIS it became apparent. The GPS was indirectly linked to various control units one of those being the front radar. As mentioned before the GPS was not giving the ADAS systems any information/data, it just happens that the vehicle software had been programmed to fault a group of control units when a fault occurred with the GPS.

Break down of GPS aerial

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Volkswagen Tiguan [clutch fault]

This Tiguan came to us on the back of a recovery truck with the clutch pedal stuck to the floor. Straight away that indicated a hydraulic issue in the clutch system, so the first thing our technician did is check for leaks. Under inspection clutch fluid was pouring out the bellhousing and in this scenario the only real option is to estimate the customer for a clutch & slave cylinder replacement as removing the gearbox to inspect what is causing the issue is a considerably big job in itself therefore estimating for the worse case scenario is sensible. Fast forward to receiving confirmation and removing the gearbox this is what was revealed.

A piece of the clutch pressure plate had pierced the slave cylinder obviously causing the clutch system to lose all hydraulic fluid into the bellhousing.

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Obstructing ADAS sensors

Advanced driver assistance systems (ADAS), we have worked on most variants of these systems and it has become a big part of what we do at Autotest. ADAS sensors in general need calibrating after various procedures. Predominantly we see body work removal or interference with geometry as main reasons for vehicles needing autonomous driving (AD) sensors calibrated.

Having a warning message displayed on the instrument cluster reading “radar signal blocked” is sometimes not as obvious as stated and many things can cause this message to display. If the radar is not seated in position correctly or the bracket is bent (usually after an impact) the radar will be facing the floor and will register as obstructed.

The vehicle in the image attached came to us after accident repairs to the front bumper for ACC radar calibration. This radar is calibrated dynamically, which means putting the radar into a calibration mode and driving the vehicle. The first calibration attempt failed so we removed the radar cover on the lower front grill to inspect the radar unit itself. Revealing an obvious blockage, incorrectly fitted headlamp washer pipes directly in front of the radar.

After moving the obstruction and re-calibrating the radar calibration was successful.

image: Radar sensor unit positioned centre lower front grill obstructed by headlamp washer pipes





Oliver GrahamObstructing ADAS sensors
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This Audi arrived through our doors a non-runner after breaking down on the customer a day or two previous. We were informed it would start and immediately cut out.

Our diagnostic process in most cases starts with reading the Error memory on the significant control unit, in this case we used Bosch’ ESI diagnostic software so it’s just as easy to run a system overview on the whole car. The fault code that undoubtedly stood out from the rest was ‘P001600 Camshaft timing advance (bank 1) Incorrect assignment’. This was logged on the vehicles engine management system (Diesel EDC 17C46 UDS) and was the only fault listed on this system.

This led the technician to remove the top timing belt cover for a visual inspection of the timing belt. Revealing a messy pile of debris and broken up belt. The cause of this was made clear upon further inspection, identifying a broken fuel pump pulley bolt. This had caused the belt to skip teeth on the camshaft pulley accounting for the ‘P001600’ fault code and the non-running issues. As far as timing faults go this was a pretty impressive failure and a lucky escape for the customer.

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