Have checked grounds at ecm all have continuity to ground. The relay in fuse box for ecm dose not excite. I have both 12 volt supplies to the relay. If i ground the blue wire the code goes away but I get a speratic reading from ecm relay code. Have continuity from the back of relay post to both wires at ecm.
Sn cat0279dprb902995
Have you checked the engine block ground.? Check your message inbox for a schematic.
I have cleaned every ground i found so far. All at the battery. All the ones under the cab where it tethers to the chasis. Got a socket way back in on both ends where the engine is grounded to the chassis and cleaned the ground on the block behind the alternator
Check out the schematic. It may show an odd location you have missed. Do you have any other Codes apart from the E495-2.?
No other codes. I am look at grounds on schematic. So far no new ones. According to the schematic i should have power with key off to three sides of the ecm relay I only have it on 2 no poser to 87
So no power on wire 150-C147-OR.? Go back to CONN 4, Pins 23 & 25. Do you have power at that point on 150-C212 & 150-C25.?
Yeah, no power at 150-c147. No power on 23 and 25 at connector 4
Big penny just dropped. That schematic is drawn wrong. 150-C147 should be drawn in BLUE, not red, because it will only have power when the keyswitch is ON. The only way to get power at pin 87 of the relay is if the coil is pulled in by grounding wire C903-C59-BU (Engine ECM controls that) and thus the contacts close between Pins 30 and 87 of the relay.
I thought that seemed wrong.
Try turning the key on and see if you have power at Pin 87.
Negative. No power key on
Try jumpering Pin 85 (C903) to ground. That should pull the relay in.
I did try that. When i do. The e459 gors away then a code comes up that says erratic signal from ecm relay. Wont crank
Ecm main relay data erratic, Intermittent or incorrect
1485-2
The engine temp sensor on the dash also just says faulted. With relay in normal with the code e459-2
If that pulls the relay in then the problem is in wire C903 somewhere, or in the ECM itself. By externally jumpering C903 to ground it is entirely possible that it could create other Diagnostic Codes because the relay coil is not being grounded by a "signal" (for want of a better expression) coming from the ECM
Very true. I agree its either a bad wire or ecm
I don't want to be a prophet of doom but those Kubota engine ECMs do not have a stellar reputation for reliability.
I did ohm the wire 903 from pin at relay and pin 3 at ecm with no problems. Leaning towards bad ecm. Boss said hang it up. He is calling cat to come look at it. I will post the ending problem. I really would like to know my self. Thank you so much for your help!
Sometimes ohming doesn't necessarily prpoduce the right results. A damaged wire can be literally hanging on by a thread and still pass an ohm/continuity test. However put a decent current through it and it's a completely different story. That why my suggestion is always to use a fused 5A test light from Batt+ hooked to one end of the wire with the other end jumpered to machine frame ground. If the wire will pass 5A it should be considered good. If it turns out to be the engine ECM FYI you can buy them way cheaper at a Kubota engine dealer (using the engine Serial Number) than you can from a Cat dealer. The ECM is a Kubota part not a Cat part, so go direct to the source would be my adivce.
Good to know. For both.
See this thread. @ozarkag is well-experienced on these engines. If it does turn out that the ECM is fried you could do worse than drop him a message regarding sourcing a replacement. As I mentioned above the P/N of the ECM (they come pre-flashed with software IIRC) will depend on the engine S/N. According to the system the engine for RB902995 is 8MU01585 and it's TIER 4 Final, but it would pay you to check on the engine itself. HeavyEquipmentForums
The Ecm part number for the physical box is interchangeable. However, the Cat units have different software, (of course!) And will need to come from, or be reprogrammed by Cat. Often used ones can be found. Partly because IIRC every new engine includes an ECM. . ..
I stand corrected. I thought they came pre-flashed from Kubota.
You are correct, if a new ECM is ordered it is pre-flashed. However, a Kubota engine dealer will not be able to order a new (pre-flashed) ECM for a Cat version engine, even thought there is likely a Kubota part number on the ECM. The Cat engine actually has a different timing sensor location and different programming. With the right connections, (above my level) it "should" be possible to reprogram an ECM to match a certain engine.
It ended up being a fuse under the cab that I had no clue were even there. I found six that were 30 and 50 amp fuse but they were all good. I haven’t had a chance to look under the cab since cat was out to find where they are. Can’t seem to locate them in the schematic yet.
I did get the stuff to build s test light like you recommended.
Are you referring to these fuses/relays located on the back side of the cab firewall.? You'll find them on Page 10, Grid C-11. The location "46" on the illustration below it is on Page 16.
46 is the ones I found. Somewhere there is to be more
Item #15 on the Platform Wiring.? They appear in Grid F-11 on Page 11, right between the Glow Plug and Start Relays. Also shown as Item #91 on Page 24.
I’m not sure haven’t got a chance to look yet. Just going on what cat said.
I know how you feel. Surely the Service Report from Cat ought to say exactly which fuse they found blown and what Part Number they fitted as a replacement.? It certainly should have IMO.
I’ll have to talk to my boss. He gets all the information. I don’t ever get to see it unfortunately
Did you ever find out what fuse was blown? Having similar problems and looking for possible solutions. Thanks.