I have a 2007 Concord.  When my pto is engaged, my odometer turns over also, racking up the miles.  I had Mack put in a sensor that was supposed to stop the odometer from turning while pumping.  This works for about 10 minutes of pumping.  After that I loose my rpm and have to use a stick on the pedal to finish the job.  Mack cannot find what is wrong, they say it may be interfering with the Concord side of the truck.  Concord says there is nothing I can do, that is the way it is.  Concord is telling me to put a hubometer on.  I really dont want to do this.  Has this happened to anybody else and does anybody else have fix for this?  Any help would be appreciated

oh and when I lose all my rpm, the electronic malfunction light comes on.  Everything goes back to normal when I am rigged out and back driving down the road

When your pump is all better, fixed like it was brand new. After all the lies and B S from the service managers and salesmen. When the dust finally settles; the problem will be with the programming on the &@*&#% Mack computer.

Sheppy: When the malfunction light comes on ,push the throttle sensor(+ or -) up and hold for 2 seconds.The malfunction light will blink out a code 9 ( X number of flashes followed by X number of flashes),then when you call Mack,tell them that code! Usually there is a wire under the doghouse that is loose,going to cruise control relay.

just like a bad head light switch it works and after ten minutes it is so hot it is burning the insulation off the wires. something is loose and damaged and it is not going to get better until it gets fixed.

May I ask a question when does the RPM reading come back on the unit.  The circuit works like this, the throttle on the pump uses a secondary throttle thru the cruise control, when put in PTO the ECM changes the control to the second control if for whatever reason the ECM looses the tack and or the tail shaft sensor the cruise gets shut off for a safety concern.  I have found no way to get by this. Did this happen before Mack made changes?  If so the answer lies there.  If it worked before it might work right if Mack removes what they did. Or I could be all wrong.

Pwrsurf

Hi Sheppy

  I am quite sure sure you have a Mack issue here. I have tried unsuccessfully to get Mack to resolve this for some time with no luck. Having the odometer run when the pump is running is not an issue with re-sale. Several manufacturers use this same set up. You will have an issue if you over rev your main pump with too long of a stick. Go back to Mack and have them reset the parameters to the manufacturer settings. Kerry will help them with these.

                            Be safe.       Terry

Thanks for everybodys help.  Took my truck back to Mack and got the sensor removed.  So far everything is working fine. I guess I will just have to put up with odometer spinning when I am pumping