Cat D3GLGP NO SPEED CONTROL

[DHC120644]

Hey Folks,
This is my first post but have been a regular reader. I decided to ask for your help.
I have a 2005 Cat D3GLGP (SN MHK08155) that will won't accelerate. When first started the speed indicator can be increased to full scale but as soon as it is put in forward mode it drops to zero and machine barely moves. Does anyone have an idea as to the problem? Does anyone have a electrical schematic for this machine?
I have changed the hydraulic fluid and filters as part of maintenance program. I had Cat dealer come out and after 2 trips and 5 hours for 2 service trucks, they replaced brake pedal switch($2200 charge). Two months later same problem, came out and replaced a speed servo($1200.) Problem is back again. I am thinking I have an electrical connection problem. I am tired of paying them to guess what's wrong. Any help will be greatly appreciated.

 

[Nige]

I have a 2005 Cat D3GLGP (SN MHK08155)

Unfortunately that's the engine S/N, not the machine. You need to quote the last 8 characters of the Product Identification Number (PIN). Most likely BYRxxxxx. No problem for an electrical schematic, just need the machine S/N to confirm the correct one.

Next thing you need to do is get into the electronic system in order to read Diagnostic Codes. See where the asttached gets you.
Locate the Harness Code connector (2) and the Diagnostic Indicator (4) which are down by the fuse box. Pull the two halves of the DC apart and turn the key switch ON. Then use a short piece of wire (a paperclip will probably work) along with the illustrations on the attachment to pull up, and scroll through (increment), the Diagnostic Codes. The Pin Numbers shown on the illustration are moulded into the connector. Post back with your results.

 

[DHC120644]

I have been impressed by the help you give to the members, now I am experiencing it first hand, thank you.
My dozer PDI is BYR00943. I will get the codes tomorrow.

 

[Nige]

Check your messages. An electrical schematic will be along shortly.

If you have any trouble accessing the Diagnostic Codes post back with any questions.

 

[reganj]

As per usual, Nige is going to do his best to help, He is an exceptional wealth of knowledge and was very helpful to me and everybody else. Thanks again Nige!!
PS I also have a D3G lgp. Mine ended up with both track speed sensors replaced and calibrated.
Let Nige guide you through the process and I can make a recommendation on who not to take it to.