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Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 3382
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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My Freithliner cascadia have 3 active faults Radar sa42 spn639

Customer Question

My Freithliner cascadia have 3 active faults
Radar sa42 spn639 j1939 network 07
Chass controller sht lo 216s254 04
Chass sa71 spn 520409 04
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Customer: replied 2 years ago.
Cascadia 2010
Expert:  Jeremy replied 2 years ago.
My name is ***** ***** I will assist you. For the Radar code, see this link here. Look at the code for 43, external speaker fault. That is what that code is for. The other two codes mean the same exact thing. They mean : Trailer Stop Lamps Shorted to High Source. The chassis controller has a protection built in to keep the truck protected and from burning down. The fault is in the trailer stop lamp circuit on the trailer or the pigtail to the trailer, if the issue returns on more than one trailer. I would check the trailer stop lamp wiring and lights and verify that they are working. If the stop lamps in the trailer are burned out, or the wiring in the trailer is open, it will throw this fault code. The relay and fuse for the trailer are located in the black box on the firewall, chassis module on the driver side, the black box with the rectangular connectors. All the fuses and relays for the chassis is in there/ There should be a label in the cover. Check relay 7 and swap with a known good relay and see if the issue goes away (if the trailer lights are not working) for that relay going bad will also trip that code. You will have to cycle the key a few times after swapping that relay if it is the relay at fault. To eliminate the trailer, use a trailer pigtail tester in place of the trailer and you can confirm the issue being in the trailer as well. __________________________________________________________________________________________________________________________You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see,touch, smell, hear, or taste the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back.The system DOES NOT automatically give me credit from your deposit. A rating is REQUIRED. You are rating me for the information I provide,not the website. I have no control over the site fees, site errors, category errors, or how long it took for a response for these reasons.I am not an employee of this website, so please rate with a POSITIVE (green) rating for me to get credit for assisting you. You still paythe website for negatives or by not rating at all. I just get nothing from that payment you made. So please rate each answer I provide.I want you pleased with my service to you so please inform me before rating negative (red) and I will do my best to make it right. Followups for same question are always free after ratings have been made.I do have many workshop manuals, diagrams, etc that I pay to get access to out of my pocket. If one is needed, please ask and I will giveyou an offer at my technician discounted cost to you for such manuals. I never charge above that cost.Thank you for allowing me to assist you through Just Answer!Jeremy
Customer: replied 2 years ago.
Is SA42 SPN 000639
J1939 network 07
Customer: replied 2 years ago.
I send you the pictures but I thing is 42
Expert:  Jeremy replied 2 years ago.
These 2 pics mean the same thing. I posted the meaning of them in the previous post. They are a fault in the trailer that the chassis controller sees, the stop lamps on the back of the trailer fault. The first pic is the code in the module, the second is where the code is reading from a.k.a. the address.
Customer: replied 2 years ago.
The trailer Stop lamps work, the truck back turn lights doesn't work, I check fuses, relays, all ok I check for power in the back and I have power only in stop lights , some guy told me that problem can be instrument cluster unit, let me know if you have another idea
Best regradsNondier
Expert:  Jeremy replied 2 years ago.
The instrument cluster for no turn lights on the back of the truck? No, it would be in the relay box or a "hard set code" causing the turns lights to not engage. If you have turn lights on the trailer, then the codes just need to be reset. If not, then there is a short going on that needs to be chased to the module on the frame to see what the cause is. The cluster would have different codes or just dashes if it was the reason for anything.
Expert:  Jeremy replied 2 years ago.
I see you viewed my response. Do you need any more assistance on this question?
Customer: replied 2 years ago.
Hi Jeremy the electrician check the cables and he said everything is ok( cables). Now he said the problem can be the Sam chassis box, It is possible? the Sam box can create that problem? I have turn lights and for way emergency in the trailer but not in the back of the truck
Expert:  Jeremy replied 2 years ago.
Yes it can, if it is tested to be bad. All the electrical goes through that module. It gets the signal in and then sends the power to the trailer lights. If the tech tested it and it was confirmed that it is getting the signal, but no power going out, then the module is bad.
Expert:  Jeremy replied 2 years ago.
Have the tech check for power coming out of the Sam module to the relay. If no power, then you know the SAM is bad.