220 Volvo electrical gremlins

[oldtimer53]

Our 220D loader has warning messages that all refer to error monitoring temperatures, Engine coolant, axle temp, hydraulic temp, coolant inlet temp.
The V-ecm is connected to all the suspect sensors, and all share an analogous ground. I have measured the resistance of the circuits, and checked the sensors against the value of a new sensor. All circuits are good, with no indication of a short to power or ground. Checked all the way back to the Ecm, OK. The sensors are all the same P/N, and the Ecm provides a 5 volt source to each. They do show changes in resistance with a change in temperature. Volvo is very mysterious about providing any info, other than I have been able to confirm that the 5 volt is correct. Anyone have any ideas? I am leaning towards a bad Ecm, but $3000 is a bit much to substitute a known good unit(new- non returnable part).

 

[95zIV]

Trade it in for a cat, kawasaki, deere, or komatsu.

 

[MKTEF]

How is your voltage rating?
Been out for some strange messages, when the alternator brushes is worn out and the voltage is slowly dropping.

The old brains could be reset by taking all the connectors out and putting them back in.
Could be worth a try?

There is also no secret that the 220 and 330's are not the same quality as the rest of the Volvo line. They share to much with the old Michigans......

 

[oldtimer53]

Alternator is charging 28.9, I have had the Ecm unplugged to test circuits, checked voltage with it hooked up. The dumb thing is that they are only 2 wire sensors, usually 5 volt sensors are 3 wire. So the ECM must be seeing a voltage drop or load on the signal, instead of a return voltage(passed through the sensor.
We have Cats and Deeres. The 980 doesn't have the balls or climbing ablility of the volvo, and the 644 is light in the ass when loaded. You barely have to crack the throttle 1400-1500 rpm and the volvo will walk through a 35 yd pile of anything without digging a hole.

 

[superwrench0166]

Have you checked to make sure when you conect to the sensor or any other conector for that matter that your not loosing connection. i have seen it many times someone starts probing conectors for a problem never get it fixed and i go behind and find the pins no longer making good connection.

 

[komatsukid]

Buying a Cat, Komatsu or John Deere wont change anything. Wiring problems can be some of the most difficult problems to figure out. Unfortunatly I dont have any suggestions. good luck.

 

[CarterKraft]

not sure how a 2 wire 5 volt system is going to work?

Is there a possibility that you are reading pull-up voltage for the sensors?

I would run a new ground to one of the sensors and see if it changes.

Also short the sensor wires and see what the change is.

then open the wires to see a change, this assumes the wiring is good,
not open and less than .5 ohms resistance.

on the surface it sure sounds like a bad ground, the only common to the circuits,
and after thinking abouit it you probally are reading pullup voltage, since there is no sensor return the ECM would not be able to tell what is going on.

Short the sensor leads and see what happens, Good Luck.