Mackpro

It’s for your cab power. They do go bad . Mack later changed the set up to a large fuse instead of the breaker style you have .

Power comes through fuse 39 in the fuse box on the fire wall , then through the trailer ABS relay that’s in the same fuse box . Power comes out of that relay on wire # 39-B-5.0 that goes up to the trailer buss bar, then it’s connected to the blue wire that feeds the trailer

On common rail engines, there is a electric fuel pressure solinoid on the end of the fuel rail under the valve cover . It was a common problem and we had all ours replaced with a new updated part number solinoid and also harness. It caused low fuel pressure problems and low power . There is a bulletin on this from Mack and is on both MP7 and MP8 engines

Pull the fuel supply pump . Check for play in the shaft, should be none. You can spray soapy water on shaft while shooting air into the inlet and outlet abs check for bubbles, other wise here’s what we used to do . Put fuel dye in the primary (first filter) and run the engine for about 45 seconds to a minute. Shut off engine and cap off fuel return line on the side of the block above the air compressor. Hook a air pressure regulator to the inlet of the primary fuel filter inlet and pressurize to 40-50 psi . Drop the oil pan and use a black light and look for leaks. The EUP pumps will always seep fuel to an extent , but not enough between oil changes to cause issues. If you find a EUP leaking, they do make a 3piece lower o-ring for damaged bores . Also there there is a fuel galley plug behind the timing cover that can leak but it rare .

I’m my notes, on a 2010 emissions truck during a regen the boost is 1.8 to 2 psi, however it doesn’t say with or without DRV valve , only the first year or two on the 2010 emissions year trucks used the DRV , they later made a kit to delete it along with a software download

Look at the bulletin in the next to the last post in this thread

https://static.nhtsa.gov/odi/tsbs/2013/SB-10054292-5095.pdf this Bulletin might still apply even though yours is not a MRU/leu

Is the oil level over full? Fuel in the oil is a likely problem.

About 10-15 years ago I spent a lot of time trying to figure this same thing out . This was the days of many trips to Radio Shack for resistors . The temperature one was somewhat easy , I had it set to around 250 degrees. The flow meter side was a totally different thing . In the engine ecm it calculates and sets a target flow that the flow meter should be reading , if the target flow was 12 pounds and the actual flow was 2 pounds you got a fault code for low EGR flow. I believe the target and actual flow has to be within 10 pounds of each other of you got the fault code . The target flow as always changing due to engine load and rpm. I thought about putting the flow meter sensor in the aftercooler piping and seeing if it would read close enough. I lost interest and sent all my stuff on this so called EGR delete to a guy on here from up north, he was way smarter than me but I believe I gave up too after a while.

The 4094 and 5246 codes seem to always come together. We had 3 of our truck go down in one day due to these same codes. Cold weather seems to make them happen more than the summer. Poor DEF quality, bad NOX sensors, DEF doser not spraying enough or in the worst case a bad SCR box due to coolant or oil contamination from a past EGR cooler or turbo failure. On your year model the regen temps should be around 625 T1 and 880 on the T2 . As long as the T3 is higher than T2 your probably ok. Main thing Is T2 being 880 or higher. . ( Newer common rail engines have much higher regen temps ). You will usually never see a NOX reading during a regen till the last couple of minutes. Engine fuel pressure should be around 65 psi during a regen . Years ago we used to start a regen with tech tool , unplug the interface adapter (vocom) from the truck and back out of the regen screen plug back up to the truck and go into the screen where you could pick any sensor to view, I think it was Sensor Monitoring something like that , we could pick the NOX inlet and outlet and watch it while the truck continued to regen . I have all that stuff written down somewhere in my tool box . I’ll see if I can find it tomorrow

Some of our common rail engines are now over 200,000 miles and still trouble free ( all MP8) other than the fuel rail valve and pressure sensor, there are CBR bulletins on replacing them with upgrade parts and also replacing both under valve cover injector harnesses. However we still have issues with random things. Our biggest issues right now are the Mack inter wheel locks blowing apart . I wish we would order them with the inter-axle air power divider only. Also our Mack T-310 trans seem to really like to go back the dealership for hi/low synchro replacement every 18-24 months. Our last 3 new trucks have the M-drive transmissions and drivers fight over who gets to drive them . I love them , less clutch’s I have to adjust. The LCM ( light control module) that was brought over from Volvo has been an adventure. A simple lighting issue is now a major pain the the butt. ABS wiring in the frame rails shorting out the rear wheel speed sensors now cause the speedometer to quit working and derate due to speedo tampering parameter on . Had three trucks in a week have this issue. Also we have found loose main ground wire on the inside of the cab at the pass through on the firewall above the throttle pedal to be the cause of many intermittent random fault codes .

Last I heard they did discontinue the clutched air compressor but the on/off water pump is still an option and maybe standard now. Our 2018 and 2019 do not have the on/off water pump but our 2020.5 has it . Also our 2020.5 has the air governor in the air compressor. Back in the ASET days we had a fleet of CXN tanker trucks with the same air drier/air governor set up. Our 2020.5 trucks also have 2 oil filters instead of 3 and also no fuel return line coming off the head. They did away with the electric fuel pressure valve on the fuel rail . This was a common issue as all our common rail engine trucks have had them and the harness replaced .

I actually had a manual for the 5, 6 and 9 speed RVI transmissions in my tool box . All it says is “ Gear Oil. MIL-L-2104D or MIL-L-2104C. SAE 40 weight “

My parts buddy back at the dealership couldn’t find much info on it . RS686LST built 2-14-79. ENDT676 engine with no mention of HP rating. TRXL 107 trans . 4.17 Mack rears. Could not get any real info on front or rear suspension. However it did have the optional ABS brakes .

RH Sheppard has all their manuals on the website. I use it a lot . TRW used to have their manuals online but haven’t checked it a while. First thing would be to figure out which brand then which model gear box you have .

RD690P built 10-12-94 with a mechanical EM7-275 HP engine . 217” wheel base , 12,000 pound steer axle , spoke front and rear hubs, 5.02 Mack rears , Mack 5 speed trans T2050, spring rears but not camel backs .

https://www.bigmacktrucks.com/topic/29716-low-boost-wastegate-error-code-can-anyone-help/

Mack has a good bulletin on the 4-5 code on the CCRS 460 engine. Only the higher HP levels CCRS engines used the wastegated turbos. Not to be confused with the ASET 4-5 code with the VGT turbos . On the CCRS 460 , in the engine software there is derate for overboosting and if the boost is to low then of course you have low power. So the wastegate adjustment has to be set up perfect. I’ll see if I can find the bulletin

https://www.bigmacktrucks.com/topic/48125-scr-fault/

Mack had some good service bulletins on this code but they seemed to have disappeared . I’ll see if I can find a link to them

Looked up in my chart , the 380/410 and 427 are exactly the same . Same turbo and injectors ect. The 380/410 puts out 1660 foot pounds of torque , the 427 puts out 1560

The cam key way swap was only on the early Etech engines . 1998.5 through around 2001.5. After that the CCRS ETECH engines came out and from then on no more cam key way swapping

They should be pretty close to the same thing . I have a chart at work that shows part differences in HP versions . The only differences in the AC engines are turbo and injectors. Of course the engine ECM stores the HP setting as well .

A bunch of bulletins released today on CBR , CBR-2076-1 talks about new software for the P20EE code . Unknown how long the software has been out but it’s worth a try .

Check the fuse panel by the clutch pedal for water damage. Pull one of the bottom relays out and look for while crusty corrosion. There was a recall for this on some units . Follow the battery cables all the way to the starter . Look for them rubbing the frame rail or transmission. Check the ground lug welded to the frame behind the battery box. Is there any GPS/data logger/Qualcomm hooked into the diagnostic connector? We had a faulty Qualcomm cause lots of issues till we unhooked it . Check the terminal strip by the fuse box on top of the dash , there are a few ignition, battery and ground connections there , also 2 data link terminals, make sure nothing is touching them . We had a guy hook a CB up and his power wire terminal twisted over and touched the data link terminal causing a problem that took a day to figure out .