Mackpro

Lost comms on the J1939 wires ( always yellow/green twisted wires) between the engine ECM ( EECU)and the Vehicle ECM (VECU) . Fist pull the 2 connectors off the engine ECM and check for antifreeze in the connectors/ EECU. If OK pull the kick panel in front of the passenger seat and look for rubbed wires coming out of the VECU and rubbing on the kick panel, is a common problem. However normally if the J 1939 wires go down the engine will die if you shut the key off but it takes about 10 seconds. When the J1939 high speed data line goes down the low speed J1587 line takes over but every thing works slow.

We just had CV in the shop doing the same thing. The throttle pedal wires at the VECU are shorting out on the kick panel in front of the passenger seat , Pull down the black kick panel, 4 screws on top and 2 at bottom at the floor. Lay the panel down look very closely to all the wiring and how they lay and contact the panel. You will probably see rub marks on the panel where the wires come out of the VECU and ABS ECM and loop back to towards the fuse panel. Repair wires if bare copper is visible . Tape up all wires where hopefully they wont rub and short out again. We have seen this many many times. And will not set a fault code most times.

Yes yours has the Step 12B software installed

Your Vehicle ECM is at Step 12 as of now. There is a Step 12A and of course the 12B. There might be some other engine files as well. Assuming your truck is a CV713

We just did a total rebuild of our 1994 CH wrecker. Reman Mack 454 engine, injection pump and starter , water pump , clutch , new engine harness and on and on. We replaced everything from the trans forward even the radiator and after cooler . Every thing straight from Mack . Only thing we couldn't get was the ABS harness , however we ordered the ends from WABCO and built them ourselves. Cab parts however might be a different story. However we did replace the heater core and evaporator core as well. 1999 and up ETECH and CX/CH style trucks your mostly safe .

Only 2 choices. Keep your older truck or buy new and buy factory extended warranty to the max! Then trade in at end of extended warranty! Trust me! I love the older trucks but nothing beats the extra 100 cubic inches of the MP-8

3-4 Code ETECH ASET.pdf

Those sensors do just go bad over many years. Replace it and make sure you use the same shims as the old one. We used to add an extra .015 " shim on the older trucks due to camshaft endplay. If problem still happens and its causes a miss/vibration and you have a older ETECH and with the small vibration damper, We in the past have installed the bigger damper and it solved the issue. But first I'd just replace the sensor.

I will say, this is one of the best pulling trucks I have ever road in or drove. The owner picked me up and we took a load of corn to the grainery last friday. Grossed out at almost 98,000 pounds and bad injectors we had no problems in the hills or in heavy traffic. I thought it was awesome but he said it was no where as good as it usually is. Truck is a CHU daycab with a 505 PLUS MP-8, T-310 trans , Meritor rears with 3.21 gears and disc brakes all the way around. Running super singles on the back 445/50 R22.5 . No speed limiting and he dont baby it at all and still getting 6.1 MPG on his trips. I have pulled up some of his other longer and lighter trips and they were in the very high 7's .

I wonder if the Tech is using VCADS/ TechTool or the old VMACIII program to change parameters? We only use VCADS/Techtool on the VMACI, VMAC II and the MP engines. on the ETECH, CCRS and ASET engine we use the old VMAC program wecause its so much faster and easier.

Thank God for extended warranty! LOL. I got this one done in under 8 hours but if I'm not bothered and feeling good and can do one in 6 hours. The kit comes with every thing , cups, injectors, o-ring and hold down bolts.

We only program the engine ECM . Leave the vechicle ECM alone. There shouldn't be any issue as long as your engine/truck is a 99-01 etech

Anytime we see any code with "plausibility " in the definition, it's usually software related. We always update the engine ecm ( EMS) and the after treatment exhaust ECM (AMS) anytime we're troubleshooting a emissions fault. And software updates are covered under warranty for 2 years/250,000.

Any guess in what I'm doing today? 2014 CHU MP8 with 215,000 miles. Vibration under a load (97,897 pounds) . Exhaust brake pistons were tight.

Always remember that these Behr fans never totally unlock and free wheel like an air fan clutch. Also they should never be totally locked solid like an air fan as well. If the clutch/fan is locked solid to the pulley and the only way to turn the fan is to slip the belt then the fan clutch is bad and needs to be replaced. Also in cold weather it can take quite a while for them to disengage .

With the old Mack software , we usually go into switch status and see if the fan is commanded "ON" and also if the AC switch says on. Also the intake manifold temp sensor, if its over 175 it will command the fan on.

Now for something completly different. Still a work in progress as the owner says.

I believe there's a ground breaker under a black plastic cover mounted to the air cleaner housin bracket, this is all the ground to the cab. You might add cab to engine, cad to frame grounds. Worked on very few MR's as all the refuse companies and city owned MR/LE had their own shop's thank god! Lol. I looked for any diagrams that included the Allison and only had what I sent you the other day. We only have 1 old sheet on the VMAC 2 wiring .

You can get a 505 in a GU with a M drive or a manual trans but no can do with the Allison . Big differences in the thermostat housing and cooling piping on a MP engine when you got a Allison trans. However this truck with the 455/ Allison and Mack 4.19 rears works really well on and off road.

We have had very good luck with the Bendix ESP on the Mack since 2004 I believe. One of our big local chicken hauling fleets were constantly flipping over their macks till the Bendix ESP was finally installed. I don't believe they have flipped once since. Sadly our body shop doesn't get to do cab replacements like me they used to. It has worked better than I ever expected . However the Bendix ACC adaptive cruise control is a total nightmare in the macks. The seeing eye is constantly failing and getting out of adjustment . Since it's tied to the cruise control , when it fails the cruise won't work as well.

On 1998 to 2001 ETECHs , if fuel is coming out the head at the injector lines , then the o-rings on the injectors are leaking and return fuel is coming out around the injector line. If the fuel supply pump is the original then I'd replace it. Low fuel pressure can cause some crazy engine misses that can jump from cylinder to cylinder

Speaking of Mack/Volvo corporate. I spent most of last week fighting with them over specing out my good friends new GU. They finally did come out and say why the customer can't have it the way he wants it but it was like pulling teeth. Long story short , Mack makes a 505A just for Allison trans. We try to order it in a GU , . It gets denied. Come to find out the GU's radiator is to small to support the 505 and a Allison with the big heat exchanger on the back of it. However if your in Canada or Alaska you can order it. You can get the combo in a CHU but they wouldn't let us get a steer axle bigger than 12.5k. Customer was not happy however he order one any way that matches his 2016 GU 455/Allison except the new one will have the common rail motor. So far the common rail engines that we have sold have not returned with any issues, were keeping our fingers crossed. My friend has 2 CV's and this GU. Keeps them pretty clean. I spent a few days tinkering on it with some part upgrades and adjustments. Quote Edit Options Add to BMT Wiki

lol didn't mean to post this in this thread!

Sorry , I meant to post this in another place instead of here! Lol. Speaking of Mack/Volvo corporate. I spent most of last week fighting with them over specing out my good friends new GU. They finally did come out and say why the customer can't have it the way he wants it but it was like pulling teeth. Long story short , Mack makes a 505A just for Allison trans. We try to order it in a GU , . It gets denied. Come to find out the GU's radiator is to small to support the 505 and a Allison with the big heat exchanger on the back of it. However if your in Canada or Alaska you can order it. You can get the combo in a CHU but they wouldn't let us get a steer axle bigger than 12.5k. Customer was not happy however he order one any way that matches his 2016 GU 455/Allison except the new one will have the common rail motor. So far the common rail engines that we have sold have not returned with any issues, were keeping our fingers crossed. My friend has 2 CV's and this GU. Keeps them pretty clean. I spent a few days tinkering on it with some part upgrades and adjustments.

Hours are stored in the engine ECM, Miles are stored in the VECU ( vechicle ECM in cab) . You are loosing power or J1939 communication to the engine ECM.