Mackpro

Also is this a MP7 or MP8?

Looking to get you a part number here shortly

There is a 12 wire connector/harness that plugs into the chassis harness under cab . This is the manual transmission harness. It’s for the speedo sensor, reverse light switch , transmission temp sensor and PTO.

First make sure 20 amp fuse/breaker is installed at fuse 42 in fuse box by clutch pedal. More info to come

As far as Corporate helping dealers with issues like this ( change overs as they call them) it’s non-existing. They will set up the data files and if you lucky they will give the dealerships a Vin of a very similar truck as yours but with a manual transmission. Then it’s up to the dealership to go through each page of the parts look up and compare what’s different, from fuses, breakers , relays and harnesses. Been through similar situations with them years ago. They don’t make a parts list or how-to on things like this.

It’s a separate harness that plugs into the chassis harness on top of driver side frame rail. I’ll see if I can get some pics in the morning. I’m thinking the Allison harness is separate and goes directly through the firewall with it’s own harness.

The 1400 rpm is the default max RPM when there is a “Speed Error” . I always set this to 2150 in the Parameters when setting up a truck. Mack never really explained which speed error. I always assumed it was crank or cam sensor. When the flywheel was changed it’s possible the crank sensor could have been damaged as it reads off the notches on the flywheel. The truck should still start. There is a different wiring harness for manual transmission trucks . Don’t use the Allison harness

I just worked on a 2006 Volvo VNL with the pre-emission D-16 engine. I didn’t think to look at the HP rating. It seemed to run pretty strong though. Volvo pushed the VNL as their heavy haul truck with many different engine options for many years. After the Mack Titian and MP-10 was discontinued in the US , Volvo pushed the VNL again as a heavy haul truck with the D-13 500HP/1900 ft pound torque or the Cummins X15 565HP/1850 ft pounds of torque. The Mack MP8 is maxed out at 505 HP/1860 foot pound of torque. It seems the Mack 505 Plus ( 1900 foot pounds of torque) is no longer available. The 505 Plus was a beast but seemed to cause some weird vibrations when under long hard pulls in the CHU trucks I worked on . I believe the 505 plus was available between 2014-2016 and pre-common rail engines in 2017 .

On your oil level/temp sensor. It’s the same one that’s used in all MP engines. Original part number is 21042447. That part/number has been updated 5 times over the years since 2008. The new number is 23285701. And apparently there is a national back order on them .

I even found my harness I made up to test it. What I have found is the rubber insulation grommets that the ecm bolts go through seem to shrink over time and this causes the ecm to vibrate/shake and causes the ecm to fail.

The power and grounds are in the “B” connector which is the bottom connector on the ecm. Pop the cover off to tap into the wires .

Most of the time when the engine ecm dies it’s done and doesn’t ever start/ wake up again. However I have had a couple randomly die like yours. To figure it out I put a amber trailer marker light in the cab and grounded it to somewhere in the cab and ran the other wire to the power supply wires at the ecm connector. When light on I knew I had power at the ecm. Then go for a test drive and see what happens. I’ll post pin locations later

208 degree coolant temp should equal 257 degrees oil temp according to Mack. The max is around 270 best I remember

The fuse box down by the clutch pedal is know to get water in it . Do much so that they had a major recall on several thousand units from 2008 to around 2012. Sadly the CTP and CXP were not part of this recall even though the design was basically the same as the CXU,CHU and GU trucks. However the CTP/CXP fuse panel has a different part number than the 2008 and up trucks. Pull a couple of the bottom relays and if there is white crusty residue on the pins then water has been in the fuse panel and possibly needs the be replaced

Best pic on the Internet I could find . I circled it .

I’ll try to get a pic of the problem connector. It’s under the hood around the foot valve area .

The dash cluster is not needed for the truck to run and drive. Drove several around the lot with cluster removed., The 04 emission MP7 in the CTP and CXP was a a little different as it was only made for only a little more than a year. The wiring is a little different than the 2008 and up MP trucks. Power to the engine Ecm comes from the fuse panel by the clutch pedal. Fuse 38 and wire # is F38A2. Power comes through the top connector on the outside of the fuse box , PIN number A . This connector is called the EPDME. It then goes through connector CIEC pin A , this is a 16 pin connector around the foot brake valve area. This is the usual problem area. With the engine running. Shake and twist this connector.

The CXN/CHN cab is also 6” longer than the CH and CX cabs from the 1989 through 2003.5 years. It seems the “bigger “ truck drivers could not slide the seat back far enough. Oddly enough the old short CX/CH cab was brought back into production for the MD series of truck that are being made today.

Thank you sir!

Happy Birthday! I think we have something else in common other that working on Macks,

You can get new injector harness ends and pins and repair your harness . Bulletin attached injector harness.pdf