How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Andy Your Own Question
Andy
Andy, Truck Diagnostic Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1571
Experience:  International trucks, International, Maxxforce and Cummins engines, diagnostic, electrical, Hvac and refrigeration repairs
30303843
Type Your Medium and Heavy Trucks Question Here...
Andy is online now
A new question is answered every 9 seconds

I have a 2010 IC CE School Bus Wabco Meritor ABS. ABS, Trac,

Customer Question

I have a 2010 IC CE School Bus Wabco Meritor ABS. ABS, Trac, Yield sign on as is the usual with ABS problems. I have a little Bendix RDU that reads Left, Sensor, Drive Axle. I have cleared it and comes back immediately. Went back to the alleged wheel Inspected
sensor and cleaned and pushed back in all the way touching tone ring Inspected tone ring in perfect condition no obstructions Checked wheel end bearing play- no play wheel spins freely Disconnected sensor to test and read varying .25vac when spinning wheel
Checked sensor leads to ground- not grounded Swapped sensor with known good sensor no change Checked wiring from brake brain at sensor connector (disconnected) with key on 5v reference on one lead other grounded Checked wiring at connector before the brake
brain- wheel sensor .25vac varying readings go through the connector ok. Also inspected connections looks good. DC voltage with everything hooked up and key on is 2.7 on 5v reference lead and 2.2 on grounded side. Don't know what to do???
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Andy replied 1 year ago.

Hi there ! My name is Andy ! Can we start with the last 8 digit of the Vin number please along with the fault code you have for the ABS ! Thanks

Expert:  Andy replied 1 year ago.

Do you still need help with this?

Customer: replied 1 year ago.
AB176117. I don't have a scanner at this time. Is it possible to obtain a code some other way?
Expert:  Andy replied 1 year ago.

https://www.dropbox.com/s/tk6fbao5geml169/checking%20body%20controller%20faults.txt?dl=0

Try this !

Expert:  Andy replied 1 year ago.

Any luck with this?

Customer: replied 1 year ago.
Hi,
Here they are. Hope you can translate this into English.Software Rev: 4.2
Hardware Rev: C
Active Codes: 0
Total Codes: 4SPN: 7264 FMI 11
Previously Active
OC: 0 SA: 0
CONN/PIN: ---------: NASPN: 2000 FMI: 19
Previously Active
OC: 3 SA: 33
CONN/PIN: N/ASPN: 4012 FMI: 6
Previously Active
OC: 6 SA: 33
CONN/PIN: 1604KSPN: 520803 FMI: 5
Previously Active
OC: 22 SA: 33
CONN/PIN: 1601F1
Expert:  Andy replied 1 year ago.

7264 11 - Glowplug relay circuit fault, source address 0 means this code came from the engine ECM

Expert:  Andy replied 1 year ago.

33 source address means code comes from body controller

SPN- 2000 FMI- 19

message
not Received from
Engine
ECM not Programmed
for Aftertreatment,
Faulty ECM, or Faulty
Drivetrain Data Link

Expert:  Andy replied 1 year ago.

This one is from body controller too

4012-6 - Right High Beam
Short To Ground
Short To Ground or
Overload in Right High
Beam Circuit

Expert:  Andy replied 1 year ago.

520803-5 -Park Brake Relay under Current or open circuit- Could be a defective solenoid

Customer: replied 1 year ago.
The brake is from disconnecting connector with key on.
Does all the information go into the Wabco unit and then go to which computer the one in the engine compartment or another one?
Would it be advisable to swap brake brains off a sister bus to see if that's where the problem lies?
Does the brake brain have the relays inside it that relate to abs?
Need some ideas to check out stuff.
Thanks
Expert:  Andy replied 1 year ago.

I will try and locate the troubleshooting manual for you !

Customer: replied 1 year ago.
Thanks. Can't seem to clear codes. Set a new code.
Spn 2003. Fmi 9
Oc 1. sa. 23
Conn/pin ------na
Expert:  Andy replied 1 year ago.

https://www.dropbox.com/s/cundzyr1a6sd5nt/wabco%20full%20power%20brakes%202004.pdf?dl=0

Customer: replied 1 year ago.
Thanks. I didn't get the last pages of repair instructions. There are supposed to be 20 and I got 14 out of the 20.
Expert:  Andy replied 1 year ago.

Oh Ok ! Let me try again !

Expert:  Andy replied 1 year ago.

https://www.dropbox.com/s/cundzyr1a6sd5nt/wabco%20full%20power%20brakes%202004.pdf?dl=0

Customer: replied 1 year ago.
Guess it just doesn't have the last pages. I'm going to test all other sensors just to make sure they're all good.
Customer: replied 1 year ago.
All wheel speed sensors have ac voltage and ohm 1200. Decided to check codes after startup and drive 5-10 mph leave engine running got spn 791 fmi 7 oc 55 sa11. Hope this isn't just from disconnecting with key on but did that with right rear too and no other codes.
Customer: replied 1 year ago.
Did the clear code. I think it may have cleared the active code. Then drive again got spn 791 fmi 7 oc 57 sa 11
Expert:  Andy replied 1 year ago.

Ok so are all active codes gone now ?

Customer: replied 1 year ago.
Well if I clear yes. Abs & trac will stay on but the yield sign goes out. Ecu is waiting for speed test confirmation so drive 5-10 mph and yield sign Comes back on active code pops up 791/7. OC I'm guessing is the number of times this has occurred because it keeps going up each time.
Expert:  Andy replied 1 year ago.

That is correct ! Oc is for occurences . Do we know what the code is for ?