Not sure if this is the right place to post this, but here goes. Have a Doosan P185WDO compressor that nobody can seem to fix. Keeps throwing CPR code 54 for an air pressure regulator issue. Both right after start up and even before the engine runs. Most of the time, never gets past the initial start up from wait to start. Been to 2 different dealer mechanics, the last sat on it for 3 months. Not a sensor issue. Last mechanic said it was a harness issue and claimed to have fixed it. Just went to use it on a job after picking it up yesterday..Nothing. right back to the same issue. I'm my company's fleet tech with 25 yrs experience between military and civilian jobs and I've got nothing. Anybody have any ideas?
You have the operators manual with a wiring diagram in it? Is it shutting down the machine, or just throwing the code and operating fine? Is the sensor a 3 wire? If so, should be 5vdc, signal and ground. Meter it not running and at startup and see what your reference and signal voltage show, then need to find the pinout at the controller and make sure it's seeing the same thing. Pretty sure there's a way to cycle through the controller to show what it thinks it's seeing, IIRC. Also check CANbus resistors. I've worked on some Sullair compressors throwing random codes that were just a tiny corroded resistor in the harness.
What parts have been replaced so far in an effort to fix it
The only thing that has been replaced has been the pressure transducer. 5 times. Even Doosan Portable Power says its the sensor. They claim to have had a bad batch of sensors and have since switched manufacturers and solved the problem. But I can't find any service companies that even know of this issue. They just replace the sensor and it fixes the issue. I can't find any problems with pin-outs or harness, and my last doosan dealer said they did find an issue with the harness and claimed to have fixed it. Unfortunately, none of the manuals that came with the unit have any wiring diagrams to work from. Flying blind with this one
Found a diagram. Resistors all check good. No corrosion, no off meter readings. 5vdc where indicated. No values that I can find for what the sensor return should be though