Default Code 64

[johnboy63]

okay guys, I have a 99 model ch613 and it will do nothing but idle. the default code is 64 according to the cruise button. I have tried another accelerator pedal and nothing changes. So where do I go now?

[davekt]

A 6-4 Code indicate loss of communications between the VECU(Vechile Electronic Control Unit) and the EECU (Engine Electronic Control Unit). If you disconnect the ABS ECU and measure the resistance across the yellow and green wires (J1939 High and Low) you should have 60 Ohms. Make certian the key is off! if you have 120 Ohms the VECU is not seeing the EECU or vise versa. Start at the Bulkhead connector and measure the resistance towards the VECU you should have 102 Ohms, then towards the EECU you should have 120 Ohms. the ECU's must be connected. One side or the other should have 0 Ohms if you are getting this code OR the VECU and EECU are not compatable because one os off another truck or has later Software file than the other.

Mack Electrical Man.

[Mackpro]

Look for a triangle shaped grey plug with only 3 post/wires in it. It will be coming out of the firewall on the driver side and going down. It will have a yellow and green wire in it. On some trucks it also runs on top of the tranny for hooking up a auto tranny ECM. I have seen this plug on top of the trans corrode and loose connection and truck just idles at 900rpm with no throttle responce and 6-4 code active. Also unplug engine and vechicle ECM and check for corrosion on pins.

[Brian logsdon]

I've got a 2000 same model and engine same problem all resistance checks out what did you find was your problem