Cat 120M 597-14 and E192-3

[bar12]

Hello, We have a Cat 120M S/N NJD with intermittent steering codes. These codes set on startup maybe 1 out of every 20 startups. Only after engine starting the buzzer begins and steering lights illuminate. Generally speaking no codes are set and machine operates well( operates well even with the codes). One thing we have noticed is that on startup the secondary steer pump runs for a few seconds most of the time but not all the time. Is it normal for it to come on upon the machine being started? We have checked pressure as the service manual shows this code setting at over 1050 psi but we do not go over this pressure at least while the gauges are connected and we are watching! - the code will not replicate for us while we are watching the pressures. Pressure fluctuate from about 525 PSI to 750PSI constantly fluctuating unless we very carefully center the steering joystick(very very particularly; tapping with finger). Any input would be appreciated.

 

[Nige]

E192 is generated as a result of the 597-14.

Can you see any relation between whether the secondary steering pump runs when you turn the key on and the 597-14 Diagnostic Code.? Does it set the Code every time if the pump runs, or does not run, as the case may be.?

To the best of my recollection the secondary steering pump should run for a few seconds as a test every time the key is turned on. I can't find any confirmation of that though. Certainly the secondary steering pump will start to run automatically if the implement pump pressure falls below a certain level.

 

[Nige]

As a suggestion try testing the pump pressure using a gauge and compare that value to what the pump pressure sensor is displaying. This will require ET.

 

[bar12]

Thanks for the response. We have Texa software and can see quite lot of the data but not all. The 2 readings from Texa did match our manual gauges(at first we thought a bad sensor with the pulsating/fluctuating gauge. Also steering cylinder positions sensors when the joystick is centered will, from time to time bounce from 0 to something like 650%. We will recheck this Monday; we did find some of the connectors going up to the steering cylinder position sensors have some oxidation on them so we cleaned them and will retest. Odd that our secondary steering pump does not run every time. It does not seem to have correlation to the code either. We did attempt to stall the engine without the machine moving and the secondary steering did not kick in but after reading the system is intelligent enough to not kick in unless there and some parameters met - wheel speed, a miss match of steering position to what is called for etc.. Secondary steering pump does always respond when the secondary steering switch is pressed with the machine running. So perhaps the 2 things are unrelated.

 

[Nige]

We have Texa software and can see quite lot of the data but not all. The 2 readings from Texa did match our manual gauges(at first we thought a bad sensor with the pulsating/fluctuating gauge.

The only thing I can suggest under those circumstances is get ET hooked up to it and compare real-time values for the implement pump pressure sensor versus a (known accurate) mechanical pressure gauge. There is anecdotal evidence that the Texa system does not necessarily give the full picture.

Attached some info on the secondary steering system you might find useful.