Freightliner M2 106

Hello!! hopefully I've come to the right place.
working on my M2 freightliner 106 with 413k miles..
mechanically sound just minor cold start issues..
ive replaced the alternator belt and tensioner. batteries seem to be good still.. takes about 3-8 seconds to start.. crank sounds a little weak.. not sure if its just wear and tear. minor rust on some of the hardware like on the starter and some other mega fuses and power cables throughout.

volts drop down to about 10.5 or so and once started jumps up to 14.1 which I've read is normal. auto parts says the starter batteries and new alternator are in good working order. here are the check engine codes

1.Abs 136 SID 002 Fail 02
2.Ecu 128 SID 005 Fail 12

maybe someone has access to the codes. from the little information that's out there I've read that the abs has something to do with the wrong tire size??.. thinking its just the wheel sensor. hopefully someone has fixed that error code.
as far as the ecu code.. this is what I've found

"Cylinder number 5 is past its idle smoothness limit"

#1 Fuel leak at Fuel line for Cylinder #5
#2 A bad injector nozzle.
#3 wiring to the unit pump, or a faulty unit pump.
#4 low compression caused by stuck valve, or compression brake valve
#5 low compression caused by a worn cylinder

I have seen all of these cause an Governor past its limit fault code.

If it has a hard to start issue, I would look at a injector nozzle and or cut o-ring on the nozzle."

hopefully there's someone on here willing to help get me back on the road. pulled the engine cover today and found a nice rats/birds nest above one of the fuel injectors. what I'm having issues with right now is pulling the fuel injector.. is there anything i should know before diving into this? besides torque specs..being a Mercedes engine would there be any reverse threads or a specific way to do something. the dealership does not have any nozzles in stock (hasn't for some months now) from what I've been told i can clean and reseal the existing ones with new o rings which they have plenty of. ill try and upload a picture. I'm having issues with a hardline that doesn't seem to want to break loose. there seems to be a nut behind it that either has to be held down with another wrench.. is this job pretty straight forward. I've cleaned the surrounding area with compressed air.. Was a bit hesitant I didn't want to damage the threads and find out it was a reverse thread. Engine is a mbe906 I believe.

Anyone have any idea.. even if I pull the Injector i still wont have access to the nozzle right? looks like that might be on the other side of the hard line inside the engine.. anyone have a manual handy for the job/torque specs.
let me know if the image uploaded.

 

IMG 3094 — Postimages

 

so the last picture of the loose wires is probably what was used for the lights before the previous owner replaced the box.. brake lights works as well as the top brake lights that run horizontal.. i plan to swap out one of the two brake lights that run vertical with some white leds.. instead of trying to mount a different style that came with the truck.. anyone know the ideal way to wire them up so that they work with the reverse gear? I'm completely lost when it comes to any kind of electrical work.