First time poster, and currently completely confused. I recently purchased a 2015 299D with known issues and repairs to be made. I am baffled by the electrical. It first had 4 codes 346-6, 144-6, 1627-6 & 600-3, also HVAC would not operate. I am suspecting rodent damage to the several observed locations to the wiring harness. I made all the repairs to the wiring and every code went away. Machine sat about a week before I was able to go back and clean up the connections heat shrink wire ties etc. Now 3 of the original codes are back with a 4th new one. All are current above normal. 1936-6, 1627-6, 347-6 & 144-6. Also HVAC does not work, horn does not work. I have checked my connections. I am at a loss as to why everything went away with initial repairs and now back to square one. I am assuming a common problem causing all just unsure where to start.
A Serial Number would be the appropriate place I think. "2015 299D" doesn't really help much. It sounds as though you are going to need an electrical schematic. 1627 is the fuel pump relay 1936 is the hydraulic HP solenoid 347 is the Ride Control relay 144 is the back alarm relay. That most likely is a separate issue. Please give more info. does the fan not blow, no heat, no cold. What..?
Thank you for the reply Nige. Serial is JST 01199. The HVAC blower does not come on. It also didn’t initially but worked perfectly after all my initial wiring repairs. I also don’t believe the fuel lift pump is working correctly. I do not hear it coming on when the key is turned to the run position. The fuel filter water separator is only about 1/3 full. However the machine starts and runs.
Check your message inbox for an electrical schematic. I'll get back on the rest of the faults later. If you don't have one already, start looking for the basic Operation & Maintenance Manual. Cat Publication reference SEBU9084, priced at $119 to download from Cat. if you can get one any cheaper used, go for it.
Here are the troubleshooting procedures for the four Codes you have.
The sole purpose of the electric pump is to prime the fuel system after changing the fuel filter or if the machine was run out of fuel. The electric pump does not run when the engine is running. There is a suction section inside the HP pump that functions as a fuel transfer pump. That being said, the bowl for the primary filter/water separator should be full after priming the system. When you turn the key to ON but without starting the engine the electric pump should run for approximately 30 seconds then stop. If it is not running during that time then I suppose the first thing you need to check is whether or not it is getting power when the key is turned to ON.
Still searching for a cause. In removing each relay individually changes code to a -5 error. Using other relays that are presumably good from the upper portion of the fuse panel changes the codes back immediately back to a -6 error. I am reasonably convinced it has to be a single issue causing all 4 of the relays in the bottom of the fuse panel to give the current above normal code possibly a ground issue somewhere.
You have the schematic. It shouldn't be too hard to track down a common ground somewhere.
Mystery solved! It was an additional damaged switched on wire feeding the relay that activated the main power feed to the lower fuse block. All 4 codes gone. Now on to diagnosing the fuel lift pump and the roof cooler not turning on.