Machine Model D4G; Serial # MHK12262. I had a 254 diagnostic code and no machine movement, so I changed the deceleration pedal sensor, but did not fix the problem. CAT technician came out and located the problem as a left speed control sensor (part# 360-0453), but he did not have the sensor with him. Rather than pay a second callout fee, I acquired the sensor from the parts store to install myself. The sensor had been "upgraded" so it is no longer plug and play. It must be wired in. The colors of the wires on the machine plug do not match the wires on the sensor pigtail. I also purchased a receptacle kit so the connection would be more weather proof, but I really need to know which wires correspond with each other? The sensor pigtail has brown, white, Black, and blue. The machine plug has blue, blue, brown, and purple......
I can't find anything that says what wire go to what wires, my SIS account does not give me access to Service Magazines but the only thing I see is this from the wiring diagram:
I have a Black and White wire on my Sensor pigtail. What are the chances they correspond with the brown and purple wires on the diagram?
I got it wired according to the number designations given in the chart. I got called away so I won't be able to try it until Thursday morning. Thank you!
Well....I hooked up the sensor, removed all the diagnostic codes, and the parking brake won't disengage. My active diagnostic code light is off now, but the park brake stays on regardless of switch position. I had a spare park switch on the shelf, so I put it in, but no change. When the CAT tech came out, he used a laptop to determine the left speed sensor control sensor to be the problem and he said that when he unplugged the sensor the active 254 code stopped. If I wired it incorrectly, could the ECM not recognize the sensor is even there? thereby not allowing the park brake to disengage? Also, I have all the access panels off and I can hear a light buzz around where the engine marries up to the transmission when the Park switch is engaged that stops when the Park switch is disengaged....
The S/N you gave in your OP is for the engine. The tractor S/N is TLX00897. The buzz could well be the solenoid for the Park Brake valve. First up do you have an electrical schematic for the tractor..? If not click on my username and start a conversation. Send me your email address and you're welcome to it. Now to the nitty gritty. I'm not sure you had a sensor fault to begin with (your OP) because the track speed sensors (L & R) and also the decel pedal position sensor share a common power and return from the Machine ECM. I'd be willing to bet that you have either a sensor power or a sensor ground wiring issue, most probably on the wiring for the LH track speed sensor. That makes sense to me because your 254 Fault goes away when the LH speed sensor is disconnected and comes back when it is reconnected. There are three different Diagnostic Codes for the decel pedal sensor that could be affected by a wiring issue. I've combined all three into one file, attached below. Work through all of them (I assume that you have a multimeter or can get hold of one) and see where that gets you. My suspicion is that either FMI03 or FMI04 could be the Code you have.
Thanks for all the help....after running through the wiring tests Nige gave me several times and coming up with the expected results, I was somewhat at a loss of what to do next. Dozer still immobile, Park light on, Park brake engaged, no diagnostic light active on the instrument cluster....... Sitting in the operator's seat with the engine running it occurred to me that I had removed the brake pedal spring to install the deceleration sensor and the pedal was still lying there limp on the floor of the operator's cabin. So, I reached down, pulled up the pedal, and the park brake disengaged. Apparently, the brake pedal electronically engages the park brake when fully applied? Anyway, it was a good opportunity to laugh at myself. Again, thanks for all the help.
The park brake won't release if the service brake pedal position sensor indicates that it is applied. Sometimes you have to laugh and put it down to experience..... kudos for fessing up BTW. Can you get rid of your remaining Diagnostic Code now..?
Yes sir, all clear.
Good job then. Now you're an expert and possess your own Click Box you can hire yourself out to anyone in your area with a tractor that needs Diagnostic Code work....
Egan, I for one want to thank you for letting us know the solution to the problem. Believe me most everyone here if being honest have all made mistakes like that at least once, well except for me!