I have a 2004 volvo a30d that I'm having issues with. Seems like the park brake won't release and the guage on the dash for the rear brake pressure will not move. I've pulled all the air valves I can find apart and cleaned them out. Replaced 1 valve on the tank under the bed and the air dryer still nothing. Stop light/triangle is on and won't go away.
Pop the cover on the right hand side of the cab under the rear side window, should be a load of air valves, the one your looking for is the one with two solenoids on it and a pressure sensor in the middle (see attached ) check that sensor is working if it is then check the solenoid, if it's not, it's frighteningly expensive!
Do you know the specs the sensor and solenoid should be with in?
Not till I'm back at work, and that's not till Thursday unfortunately sorry
Okay let me know and I'll look into it. I did pull that valve apart and clean it out had some slimy stuff inside but that didn't fix it...
Went ahead and replaced that valve and sensor and still doing the same thing.
I am so sorry, i hadn't noticed you had replied. there isn't really any spec's per say, the following is from Prosis Manual engagement of the parking brake takes place when the two-position switch SW5501 is activated, which means that a request for engagement of parking brake is sent to the control units V-ECU and T-ECU. Automatic engagement of the parking brake can take place in case of the following events: ○ The parking brake is always active when the machine is started, regardless of the position of the switch. ○ When the software function Delayed stopis requested. ○ Request for activation of electric parking brake from the function Load and Dump brake. ○ If the brake pressure in the accumulators is Not ok (if pressure has been lower than 2.5 bar for more than 1 second). This also generates an alarm. For continued engagement of the parking brake machine speed must be below 2 km/h. In the next step the voltage to solenoid valves MA5501 and MA5502 is cut off from the control units V-ECU and T-ECU, respectively. This means that the air to the parking brake's pneumatic system is drained, and the brake pads are applied against the brake disc by spring force. When the pressure sensor SE5501 indicates low pressure, the parking brake light LC5501 is activated. Then the longitudinal differential lock is activated,
Do you happen to have a diagram of said valves and accumulators? Also I tried hooking my diagnostic compute to it but the diagnostic port doesn't seem to have any power.
hi Alcoo44
ok so your vcads/ and service socket don't have power? does your float hold on the tip lever? does the seat belt switch have power? all these are supplied by fuse 3 a 5a I have a sneaky suspicion that the wire to the seat belt switch has been compromised and blown fuse 3.
Fuse 3 is good. That's the first thing I did was check fuses. I haven't checked the relays. And the float did work a year and a half ago when the truck moved. The service socket had 4.5 volts when I checked it before I tried hooking the computer to it.
I know this is probably something you either tried or may not be possible but have you tried connecting shop air to the line to the park brake and the line the pressure switch is on to see if the brake releases and the alarm clears?
Have not hooked it into the park brake line. I've bypassed the compressor and I've tried hooking into both tanks but neither changed anything. If I bypass all the valves and send air through the air lines individually I can get the drive brakes to release and set that way. What is wierd is when it's running I get air through the tank behind the cab and air Into the tank under the bed but If I go to the valve on the axle side of that tank there's no air
But I still have this emblem on the dash and the lower air gauge doesn't move. Weather I push air with shop air or the actually truck it doesn't build.
So the sensor that provides the information for that gauge is on the foot brake valve, it's the top one on the left if you are looking forward in the seat and down onto the footbrake valve from above, swapping the sensor with one of the other two on the footbrake valve as they are all the same sensor, and see if you gain functionality of the gauge. you will have to swap sensors not plugs as the other two have different functions ( deployed brake pressure on trailer and tractor unit)
Does any one happen to know which wires in the diagnostic port are supposed to have power. Top middle has power all the rest show ground.
which diag port, the service one ( round ) or the vcads one ( rectangular )
Round
wiring diagram of that port for you
no matter what I've tried even hooking shop air to the machine the lower air gauge wont build up past there and the warnings are still on.
Have you actually read the pressure in the system with a manual gauge? and confirmed the pressure is there? have you swapped the pressure sensor over on the footbrake pedal? if you have done both those things and there is pressure there and the sensor is good then you either have a break in the wire from the sensor to the ECU or a fubar ECU unfortunately
I have swapped sensors on the pedal. Pulled the sensor off the air tank behind the cab and cleaned it out So now bottom guage now moves to middle of the green. But top one instantly buries it's self into the red. Do you happen to know where the sensors for that one is
So that one is se5201 on the attachment I sent a few posts ago, its on the side port of the vertical air tank behind the cab, the one you just cleaned out....
Does anyone have a breakdown on all these valves and what they do that's in English. Ha
bottom left of your pink circle SE5501 is your pressure sensor for the park brake circuit, the left hand solenoid MA5501 is the one operated by the switch in the cab to let air down to the park brake to release it.
Does anyone have a source or alternative solution for the foot valve for this truck volvo directly says it's back ordered and doesn't know when or if they will get any.
drop me a message, I'm off home for the weekend, but when I'm back in the office Monday I'll take a look at our stock.