wheels off now back on and PSM & ABS lights on ?

Just got car back after having wheels refurbished, and when i drove off i noticed the ABS light is on and the PSM light is on ? is this normal when all 4 wheels have been removed, will it reset it self ? or is it back to garage on monday thanks

Hello Moss I have 2k C4 with rear led lights fitted with no problems but i recently fitted an led center brake light and found that this put the abs and psm light on, the cure was to fit a resistor So i think this could relate to your leds and not the fact you have had the wheels off its worth a check mate :thumb: hth Paul

Ah nice one, ill try disconecting them and see what the score is.. cheers for that

you may need to plug the old lights in to be sure :thumb:

You'll probably just have to turn it on and of and drive 100+ yards for the ABS sensors to relearn their correct positions. The C4 hates differential travel on the wheels. At least this is the case if you rolling-road the car.

well i removed the led rears connector, started car,and the abs and psm lights appeared to be on still, so i re connected them, jumped in car drove home, half way home i happended to glance down and low and behold the lights had gone off then they came on again, so im wondering if it is the led rears ? what resistor did you add and where ? cheers

any idea what size resistor to add to the circuits to stop the ABS & PSM lihts coming on when rear leds are fitted ? thats if they are too blame, seems to be a can o worms when you search for it, it could in fact be the MAF failing, ive removed and cleaned that again, but the ligths are still on, is there any sure fire way to check if you MAFS faulty, ie disconnect and run with disconnected ? or have the codes read by a garage cheers

a sure way to take the lights out of the equation is to plug your old lights back in mine worked fine with no faults until i added the led third brake light, which then gave me the same symptoms as you it may be a coincidence, just unplugging them will not help as if they are the problem the car can't see them anyway (plugged in or unplugged) throw the old lights in :thumb: that way you will 1000% know if they are the fault

refitted old lights, well bulbs, to make car think it had the old lights in, and no difference, connected up to a code checker at local garage and it would only read the engine codes, wouldnt let us do ABS or AIRBAG, but it did show a fault on the brake pedal switch ??? odd , but seeing as they are only 13 quid Im going to change that, wondered if the lights will reset themselves if that is the fault ? or do I have to disconnnect the battery to do a reset ? I will take it to a auto electrician, but the man I use ADT is currently on hols, back a wks time, so its down to me to try and diagnose it ( with the forum help of course )

unfortunately it sounds like the same symptoms but a different fault, when i put the rear centre led brake light in it showed the psm and abs lights, i put the old light in and it cleared, not enough resistance on the circuit with all the lights being led and drawing low current But it did clear without a reset once the problem was resolved with a resistor :? it was worth a try, as it was free, good luck with finding the fault :thumb:

thanks for the advice any advice is helpfull to a virgin 911 owner ok so im now upside down in the car, head deep in footwell looking for a damn brake switch to see if i have the spade version or pin version, can i find switch can i hell ! where the devil is it, is in in the bonnet area ? or am i just doing the usual man thing, cant see it !!!!

no17 is the brake switch

The brake light switch fixes into the bracket like a bayonet fitting - you turn it 1/4 turn to release it. There is only one type of switch - they all have 'spade' connections for the plug. When you fit the new switch, pull the plunger all the way out first. When you fit it, it will set itself to the correct length. There are two sets of contacts in the brake switch - one normally open, and one normally closed. You can get situations where the brake lights work fine, but still have a problem with cruise, ABS, etc. The latest switch should be brown, so don't think that you have the wrong one if yours is a different colour. Not a very good giagram, but the brake switch is No.1

These damn 996's work in funny ways.. as you are aware ive had ABS & PSM lights on dash since I fitted rear led lights, so i thought that was the problem, well, ive had maf off and cleaned, no joy, had lights off, no jog, jad brake switch off cleaned, no joy, well today I was thinking about getting the led rear light strip , so turned car on, wedged bar against seat and brake so i could check lights, turns out the one on the spoiler worked, the one on the car didnt,?? so i removed had a look , wiggle, light on, wiggle light off, on closer inspection the wire had come loose from the connection, so i resoldered and re fitted ( incidently they appear to be both led is this a porshce upgrade ? ) anyways, jump back in car, remove pole from brake pedal, and hey presto, ABS & PSM lights are gone.. turn PSM on with switch and off with switch all good, drive home, all good so looks like its cured, odd though, but hey ho