Help with Cat 252B skidsteer

[s_murphy]

Hello all,

I'm having some trouble with a 2006 Cat 252B skid steer. The problem is it will only start and run. The park brake and arm bar light will just flash after the machine is started and will not do anything else. This is all I know.....trying to purchase a service manual right now is a last resort, it is not the arm bar switch, it is not the seat switch, the cooling fan is working, and i did find some bare (not broken) wires in the harness where it rubbed through on the frame under the cab. I will eventually buy a service manual for it but at $625 on ebay or $834 from CAT its a tough pill to swallow right now.

This problem started out as a intermittent problem that seemed to be related to wet weather. When it first started we brought it to our shop to try to diagnose what was wrong with it. Never could find a problem and the entire time it was stored at the shop (2 months) it never had a problem. While it was at the the shop it was stored inside. When it left the shop it was stored outside and the problems began again. Now the machine is down completely and I cannot seem to find whats wrong with. Any help/advice would be appreciated.

 

[Cmark]

There's a fairly involved troubleshooting procedure for this, but let me try and give you a couple of shortcuts;

Find the interlock ECM. It's under the floor where the driver's feet go on the left. You may find it's buried under a foot of ****e. If it is, dig it out and remove the electrical connector. Check the connector pins for corrosion. Unbolt the ECM from the machine and check if the case is corroded through. If it's all OK, put it back together. Spray the connector and pins with WD40 or suchlike before you plug it in.

Next, pull up the rubber boot around the RH joystick. At the front, you'll see the elecromagnet which makes the float detent work. If this is rusty and falling apart you'll need to replace it.

In my experience, this will find around 80% of the failures, but if all looks good so far, you're going to need a digital multimeter to make some Ohm measurements. Let us know how you go.

 

[s_murphy]

There's a fairly involved troubleshooting procedure for this, but let me try and give you a couple of shortcuts;

Find the interlock ECM. It's under the floor where the driver's feet go on the left. You may find it's buried under a foot of ****e. If it is, dig it out and remove the electrical connector. Check the connector pins for corrosion. Unbolt the ECM from the machine and check if the case is corroded through. If it's all OK, put it back together. Spray the connector and pins with WD40 or suchlike before you plug it in.

Next, pull up the rubber boot around the RH joystick. At the front, you'll see the electromagnet which makes the float detent work. If this is rusty and falling apart you'll need to replace it.

In my experience, this will find around 80% of the failures, but if all looks good so far, you're going to need a digital multimeter to make some Ohm measurements. Let us know how you go.

Cmark,

Thanks for the reply. I have already removed all the deutsch connectors and put them back together with dielectric grease after cleaning them with wd-40. I did not totally remove the ECM and check the case.

I already found that magnetic switch you spoke of on the right hand joystick and it was destroyed. Do you think that it is causing my problem? I already had a friend of mine who is also a mechanic tell me that switch is most likely the cause but I needed to find a way to verify it before I spend $300 plus on it.

How does that switch tie in to the park brake circuit?

 

[Mobiltech]

If you can find someone with cat ET they could hook up and tell you in minutes what the problem is. It could easily be the magnet or the pilot lock solenoid in the right joystick. Any short or open circuit can cause it to stay locked in park.

 

[Cmark]

The interlock ECM won't activate the hydraulics unless it reads that the float electromagnet is in good order, the logic being that if the magnet is energised, the joystick is in float position and the hydraulics are activated then the bucket will fall to the floor.

Mobiltech, to the best of my knowledge unless something has changed with the B series, ET will not read the interlock ECM. Only the auxiliary hydraulics ECM.

 

[s_murphy]

The interlock ECM won't activate the hydraulics unless it reads that the float electromagnet is in good order, the logic being that if the magnet is energised, the joystick is in float position and the hydraulics are activated then the bucket will fall to the floor.

Mobiltech, to the best of my knowledge unless something has changed with the B series, ET will not read the interlock ECM. Only the auxiliary hydraulics ECM.

Cmark,

I order the switch the morning. Ill let you know what happens Monday when I get it. The switch is screwed anyways (only copper windings left) so even if its not the problem that switch will need replacement. Thanks

 

[Mobiltech]

The interlock ECM won't activate the hydraulics unless it reads that the float electromagnet is in good order, the logic being that if the magnet is energised, the joystick is in float position and the hydraulics are activated then the bucket will fall to the floor.

Mobiltech, to the best of my knowledge unless something has changed with the B series, ET will not read the interlock ECM. Only the auxiliary hydraulics ECM.

I think it has changed. I have used ET on the B models to troubleshoot seat and armrest switches.