Richard 86

Do you remember if that one faulty coil gave you codes for multiple cylinders or not? Wonder how they established which coil it was. I guess you could use trial and error if it consistently throws an error.

Well overdue update Temporary switch for MOT worked fine. Swapped for stalk switches for a second hand unit and all is fine now.

Cruzing down the motorway yesterday, and the orange engine management light started flashing. My general rule of thumb is if it's red, pull over, orange, take it easy and just get home. It flashed for about 60 seconds, then turned off for a bout 5 minutes, then flashed again for about 60 seconds then never came back on again. Car drove fine with no other symptoms. Read the codes and had seven codes. P0300 (multiple missfire) and then a code for a missfire on each cylinder. Apparently, if it flashes, then it's serious and you should pull over. Oops. Something about preventing excess fuel knackering the cat. So what are the suggestions from here? I was going to check for vacuum leaks. Figured it can't be plugs, as it probably wouldn't be all six. How does the car know there was a missfire in all six cylinders? Also, how does it know that the cat is at risk of overheating overheating? Understanding what data the ECU uses to trigger faults gives me a little more information. Since the car drove fine, I tempted to believe it's a false error, but unsure at this point.

Ok, update. Unplugged the fuse box in the passenger footwell. Managed to drop the relays box enough so I can remove the relays. After plugging everything back into fuse box I started jumping the relays. Turns out, of the three relays it's the middle one. Small blue thing. Rear fog lights both came on. FYI, grey one is the blower fan if of any use to anyone. Relay seems to work fine. So now just need to work out why the relay isn't being triggered. Ordered a second hand stalk switch thingy from eBay to check if that's the issue. As the mot is fast approaching might just wire my own little switch for now.

Ok update. I've been yanking on the wrong relays. I hard wired the terminals on the blue right relay visible from the footwell and the taillights came on. So after removing the glove box discovered another blue relay much higher up. See pic. But it's impossible to reach without removing the whole fusebox and ECUs. Is there another way to get this blue relay I'm not thinking of?

I've had another look today. I can only find two small blue relays above the passenger footwell. Right behind the fuses. One is definitely the front fogs. Identified by following the clicking sound. When I pull this relay, the dash still illuminates to say the front fogs should be on. I swapped the two blue relays round. No change. There is no click to be heard when switching on the rear relays and no illuminating dash light. This leads me to believe it's either a faulty switch. Or. The ECU which must tell the rear fog lights they can turn on is not passing the signal on. Does the lack of dash light illuminating narrow this down?

That's for the diagrams. Just had a go at lying on my back in the footwell to find that rely box no. 1 and it's hiding. I'll try in the morning when there's light and hopefully no rain. I wish car makers would insist on hiding fuses and relays above footwells. It's just rude.

Hi, my rear fog light appear to have stopped working and I have an MOT coming up soon. Checked the rear left bulb. Worked fine. Checked 7.5amp fuse in passenger footwell. All good. Does anybody know where the relay is? I've opened the relay boxes in the engine bay and non are marked as fog lights. User manual contains no useful info. The indicator on the dash doesn't doesn't illuminate if that narrows the problem down. I'm only using with dipped lights. Thanks

@ColinBarber thanks for the useful info. After finding nothing obvious in the dash I removed the camera. I wasn't expecting to find anything as the issue seemed to disappear after hitting the dash so I was convinced the problem was upfront. Anyway, the camera had aluminium oxide all over it. I pulled it apart (had to drill out some of the screws) and noticed that the two circuit boards inside the camera came apart really easily. Almost fell apart. They joint with a electrical connection thing. On reassembly the two boards clipped together much more positively. Aluminium oxide doesn't conduct electricity, but maybe it forced some of the components apart? Not sure. Anyway, so far it's worked perfectly since and not a penny spent. Always happy with that type of result. It's been a week now so pretty confident it's sorted. Thanks again.

Hello, a couple of days ago my 06 RX400H screen developed an intermittent fault where it would have horizontal lines only when viewing the reversing camera. Some times it's fine, sometimes there's two or three black lines, sometimes there's about 20 lines and it's impossible to use. I suspect the fault is in the dash, as sometimes (not always) it works fine if you give the dash near the screen a good whack. I pulled the radio and screen out today and couldn't find any loose connections or anything. Oddly there is one plug in the radio that has two wires. If this plug is not connected neither the reversing camera, maps nor the climate control will work. This means it could either be the radio or the screen computer that are at fault. I suspect the processing for the camera happens in the radio and it send the image to the screen, but this is a guess. I really don't want to play the trial and error game as even second hand, each item involved is £150+. So if I swap the screen, radio and camera and still no luck I'm £450 down. So, any suggestions how to narrow down the issue further?