i had a problem on friday. for no reason a buzzer sounded and a red light came on in the dash saying BRAKE AIR. i nursed it into an ind est with a loss of approx 75% braking efficiency and parked up. scania turned up and followed me back to base (problem had gone) and replaced the ABS lead. we thought that was it but it happened again today. running along the motorway, buzzer/red light so i pulled over, jiggled the lead, switched the engine off and on which (seemed to) solved the problem. i finished my run and reported it when i got back.
any ideas what this is? i would say air leak but there is no loss in pressure (on the gauges) so im stumped. it wasnt looked over by the fitter at all. the lead was replaced to show that he had done SOMETHING
It can be a number of things, the best thing to do is if it does it again, Don’t turn anything off, leave it running so the fitter has somthing to work with when he arrives, it is the hardest thing in the world to fix a fault that is not there anymore
A 75% braking efficiency is not allowed to happen , you probably just felt the pedal a little different as whe the ecu picks a fault up it will revert back to a pure air braking system with no electronic assistance, it really does make a difference, it means you have to push the pedal down a lot harder to the get the same results.
Does it do it with the same trailer or different ones or even without a trailer , it could just be the trailer at fault, if it goes away when you giggle the lead then it might just be the socket on the truck or trailer, maybe a loose wire?
Your truck should be running an EBS system (disc brakes?) in which case you should have a 7 pin EBS lead, not a 5 Pin ABS lead, check you have the right one on, it does make a difference.
Check your fuses there a number of fuses on the fuseboard to do with trialer ABS/EBS, Trailer ID etc etc,
I’ve had those symptoms with a Scania recently, the warning light and buzzer on etc and it was a problem somewhere in the ABS wiring between the unit and trailer. I dropped the trailer and waited for another unit to turn up to collect it then ran back to the depot solo. On the run back there was no problem with warning lights or brakes. The fleet engineer told me they had had this problem with several units, all Scania’s as the fleet is an all Scania fleet. The fleet guy knew what the problem was as soon as I called him to report the fault but said it wasn’t a quick roadside repair and as I wasn’t far from the depot, Brampton Hut to Bedford, it was better to send someone to collect the trailer and for me to return solo.
ive had somthing siliar to this 2 or 3 times each i connect the ebs lead to the trailer = a constant low air pressure warning each time it turned out to be a bent pin on the trailers ebs/abs socket
Discopete:
A 75% braking efficiency is not allowed to happen , you probably just felt the pedal a little different as whe the ecu picks a fault up it will revert back to a pure air braking system with no electronic assistance, it really does make a difference, it means you have to push the pedal down a lot harder to the get the same results.
It also seems to happen when going from Volvo to Scania After you’re accustomed to Scania and go back to Volvo you are going to fly through the windscreen. I don’t know if Scania has invented brakes in R-series, but at least in 3- and 4- series brakes seem to have only 75% efficiency compared to Volvo
I’d think the only thing bringing braking efficiency down for a 75% would be brakes fading due to heat. If air pressure would came that low I’m sure “spring brake” (parking brake) had been applied much before that.
i only pull one trailer and i am the only one who pulls it but the unit is shared. i use it during the day, the other guy trunks at night with a decker. i have reported it again today to have it checked out properly but as i need the tail lift, they wont put it in til saturday when it wont be used
scanny77:
i have reported it again today to have it checked out properly but as i need the tail lift, they wont put it in til saturday when it wont be used
If they have replaced the ABS lead and the fault hasn’t shown up again I would say the lead was the problem. It is a pretty well reported fault and it is down to something in the ABS wiring, the lead itself or another part of the circuit, in your case it seems it was the lead. The case I had it wasn’t as changing the lead didn’t solve the problem.
scanny77:
i have reported it again today to have it checked out properly but as i need the tail lift, they wont put it in til saturday when it wont be used
If they have replaced the ABS lead and the fault hasn’t shown up again I would say the lead was the problem. It is a pretty well reported fault and it is down to something in the ABS wiring, the lead itself or another part of the circuit, in your case it seems it was the lead. The case I had it wasn’t as changing the lead didn’t solve the problem.
they changed the lead on friday. the fault showed up again on monday
the trailer did have an inspection today which it passed with flying colours although it was noted that the ABS light came on. i didnt know the trailer had one on it
fitter come out and couldnt find a fault so i followed him to banbury and he plugged it in the computer and it said no fault. so in the end they disconnected the buzzer snet me on my way and told the burton dealership to sort it.
it happened twice today in livingston. not good when the place is white with snow. i tried both ends of the ABS lead (it is 7 pin) but to no avail. switching the engine off and back on seems to be the easiest way to fix it. i cant help wondering what the underlying problem is though
Discopete:
A 75% braking efficiency is not allowed to happen , you probably just felt the pedal a little different as whe the ecu picks a fault up it will revert back to a pure air braking system with no electronic assistance, it really does make a difference, it means you have to push the pedal down a lot harder to the get the same results.
It also seems to happen when going from Volvo to Scania After you’re accustomed to Scania and go back to Volvo you are going to fly through the windscreen. I don’t know if Scania has invented brakes in R-series, but at least in 3- and 4- series brakes seem to have only 75% efficiency compared to Volvo
I’d think the only thing bringing braking efficiency down for a 75% would be brakes fading due to heat. If air pressure would came that low I’m sure “spring brake” (parking brake) had been applied much before that.
I find that with DAFs, compared to Volvos.
The 18t LF I drive now is ok, but the 14t LF I drove before was a bit ‘all or nothing’ when you braked.
, you probably just felt the pedal a little different as whe the ecu picks a fault up it will revert back to a pure air braking system with no electronic assistance, it really does make a difference, it means you have to push the pedal down a lot harder to the get the same results.
After you’re accustomed to Scania and go back to Volvo you are going to fly through the windscreen. I don’t know if Scania has invented brakes in R-series, but at least in 3- and 4- series brakes seem to have only 75% efficiency compared to Volvo 
