Cat 345BL - 5WS0295 The engine oil pressure alarm is sounding. Replaced the oil pressure sensor - (quick and cheap) Replaced the engine wiring harness - (lots of bare copper where insulation was cracked off) The old monitor and new monitor both sound the alarm - (old one has been wet too many times, screen comes and goes) I put a mechanical gauge in the oil galley by the ECM and it reads 45-50 psi on a cold start. So far in trying to run down the problem with a multimeter I've noticed that there is 6.5 volts DC between wire 993-BR and ground anywhere on the frame. Is this normal to have positive voltage between a sensor common and machine ground? Thank you in advance, Fred
Maybe Nige will post a schematic for it and then the real troubleshooting will begin. Have you tested the engine to frame gound, the frame to battery negative ground, cab to frame ground, computer case to battery negative ground. These are some simple things to check, along with is there any active codes on the machine. If the harness was as bad as you say, am guessing there was a lot of hours on unit. Best to do more trouble shooting before buying any more parts. Have to see the schematic before offering my 2 cents. Someone else with the schematic may offer more. Simon C
993-BR is the common sensor ground back to the ECM. The power wire is 997-OR. Between that wire and 993-BR you should have 5 +/- 0.5v DC. If you unplug the 3-pin connector and measure the voltage between any engine sensor signal wire and machine frame ground and you should also have something of the order of 5v. This is the "pull up" voltage sent out by the engine ECM to allow for diagnostics of the sensor signal. I may be wrong but I don't think there is any way of accessing diagnostics via the Monitor Panel. AFAIK it requires Cat ET hooked up to the machine. Check your message inbox for an electrical schematic. FYI the Serial Number is missing a character. There should be 5 after the "5WS", you only have 4. I'm assuming that the correct S/N is likely to be 5WS00295. Please confirm.
5WS00295, you are correct. I'll do some checking this evening, but I'm certain when I discovered the 6.5 volts between sensor common and frame ground I also have spot on 5.0 volts between sensor hot and sensor common as is should be. I believe there was also 5.0 volts between sensor hot and frame ground, but that I will check and report in a few hours. Thank you both for your replies.
If your multimeter can read duty cycle % it may also pay you to hook it up between the sensor signal wire and the return and monitor how the duty cycle of the oil pressure sensor changes from engine stopped to engine running.
I unplugged all the sensors except the oil pressure as Nige suggested in another thread, still had the alarm. I have a suspicion that the 6.5 volts between ground and sensor common may be a characteristic of the noise suppression scheme employed to keep the sensor data clean. But this is above my understanding. Since the temperature sensor is working fine and also shares this common wire, I think I should assume the pressure sensor is also working and look into F400-GY-18. It runs between the engine ECM and the Engine/Pump Controller. I pulled error codes as Simon C suggested and found these: 4103 - Proportional reducing valve circuit is open 4204 - PWM sensor of pump delivery pressure is shorted to body ground 6200 - (no info found yet) I'm going to trace these in the schematic to see if they all run a similar path, then physically check the harnesses after I move the machine to a better, drier spot. Any info on error code 6200? Thank you both again, I'll post more as I go. Fred
I will have to look for a meter that reads duty cycle for this and future projects...
It passes through at least 4 major harness connectors between the engine controller and the pump controller. It may be worth investigating those connectors, also maybe even run a bypass wire from one controller direct to the other for a test.?
I ordered Deutsche connectors, tools and wire last night so I could do just that in a non destructive way. I've learned a lot from you guys on here, it's a great resource.