Warning lights and wipers constantly on

[stevieb123]

Hi folks,

I’ve recently joined the forum and found it extremely useful in helping me deal with some of the problems I’ve had with my E90 320d efficient dynamics. I’ve had this car several years and really don’t want to part with it but just last week the connected drive failed to turn on which of course meant no entertainment and no access to other things like initializing the flat tyre monitor. As it happens, the drivers side tyre was getting worn and past its best before date so I took it to have a new Pirelli fitted. I don’t think this tyre change has any bearing on what happed next but I thought I should mention it. The following day I decided to remove the radio/sat nav unit to see if there was a loose connection or the fuse had blown on the back of the unit. I couldn’t spot anything obvious so refitted it and it worked! However, I then had warning lights for the airbags, seatbelts, traction control, ABS and the windscreen wipers would not stop working. I looked this up and a wiring connector in the footwell and the JBE were suggested as possible causes. I reached under the carpet (as far as I could) to wiggle any connector I could find (no change). Removed, checked (with a meter) and reinserted each fuse (no change), removed the JBE and looked for any obvious damage (no change). I then checked the the alternator output and found it to be around 14.8v and decided it could be an overcharging problem. I removed the alternator and replaced the regulator (checked with Valeo it was the correct one) the regulator brushes were very short but the copper rings on alternator seemed ok. Refitted the alternator and checked the charging current which had gone down to 14.6v. The warning lights and the windscreen wipers were still on but from reading the forums I think this was still worth doing as the car has covered 175k miles. Next I bought a relatively cheap OBD scanner and found one fault code P0500 #07E8 ‘vehicle speed sensor A Circuit’. I thought perhaps one of the wheel sensors or reluctor rings was damaged or corroded, which seemed to make sense as all of the warning lights and perhaps even the windscreen wipers relied on measuring the speed of the car. I had read somewhere that the rear passenger side sensor was the most crucial one so I removed it and found the end of the sensor was damaged. Ordered a new one and fitted it with a washer to see if this (at least temporarily) would resolve the issue, but the warning lights and wipers remained on. I cleared the fault code with the scanner several times and test drove it in between but but no change. I had of course removed the wiper relay at this stage and even tried replacing it. Last night I forgot to remove the scanner and was awoken (as were my neighbors) by the car alarm going off. The battery was completely dead as I could not unlock the car and even though the alarm was sounding the indicators were not flashing. I opened the car door with the manual key and crawled through to the boot to disconnect the negative lead. I knew the alarm would keep going but had to try something. Eventually the alarm stopped. Today I have left the battery disconnected and hooked up a charger in the hope I can then reconnect it and disarm the alarm. I’m now left wondering if all of these problems have been caused by a failing battery. This didn’t occur to me because the car never fails to start. But perhaps the connected I drive system failed first because it is the most sensitive to voltage and then the JBE began to fail next because of low voltage (or high voltage as the alternator tried to compensate for a failing battery? I guess it’s becoming more obvious that I should get the battery changed and recoded as this is a simple fix. I’ll let you all know if this resolves the issue but perhaps it’s going to be a lesson to not overlook the bleeding obvious 😁

[amg6975]

Using paragraphs is helpful. Sounds like an issue with a CAN bus.