563c wheel buncher JCB00321. Oil pressure reads 34psi continuously, engine running or not. Found engine oil pushing into the plug, so I replaced the pressure sensor which changed nothing. Ohm tested the three wires to ecm plug all checked ok. Three wire sensor. I have 5volts supply voltage . The signal wire has 1.66 volts engine on or off. When I have the oil pressure sensor unplugged. The signal wire reads voltage close to 12v. Any ideas would be appreciated .
5v power is stabilized sensor supply voltage from the ECM. 1.66v ought to be pull-up voltage from the ECM seeing as the EOP sensor is a PWM type. Can't explain the 11.11v with the sensor disconnected. Do you have a schematic.? I can send you one if you need it. I think that looks like an ECM or software issue. Try re-flashing the ECM with the latest engine software . If that doesn't fix it then I'm thinking the ECM has a fried board component.
you could unpin that signal wire from the ECM and sensor and replace it with a temporary jumper wire to see what she reads. I am moving to that as a standard trouble shooting technique because that way it tells you very quickly where the wire(s) in question are good or bad or if it’s the component.
Well other than the wire, that flash/ecm replacement takes me out of the picture. Thanks for the offer on the wiring schematic but I already have one.
I agree with that. I am now in the habit of unpinning the wires directly at the ECM connector and hard wiring the sensor just to confirm that the harness is not an issue
After paying more attention to the wiring harness, I discovered that pin1 and pin 3 on the sensor plug we're backwards. Pin 1 should be 5v ref and pin 3 should be signal wire . Swaped them and all works good . Thanks.
I wonder how long it had been like that..?
Me too . This machine has exhaust issues and is locked out and will only run 30 seconds at a time. While I was determing that there was nothing I could do because factory password are needed . When I was looking at the data I realized that the oil pressure was at 34 with the engine off. Needed to be fixed anyway !