Wiring Diagram Caterpillar 3126

[Dorothy Gouldie]

VIN4UZAAHAK42CJ83609 Chassis J83609 engine CKM23163. Engine cranks and cranks but will not fire up. Dash idiot lights normal. However I do not see the yellow check engine light on or flashing. Also, I cannot read out the Diagnostic codes via the cruise control steps. Oil/lube and filters change in Oct-2018. Ran fine then. Read a post I should at least see the tach needle move when cranking -- It does not move a bit. Also , the high beam blue light will not light? last ran to storage in Oct. Every 3 weeks I run the generator to charge the batteries.

Possibly a fuse to the ECM, if no power there it will never crank and to my knowledge that is the only electronic possibility. I've had that to happen to me on my Detroit engine. Other than that on a diesel, there is fuel or the lack thereof either by stopped up filters, or a lift pump not pumping.

One way to check if the pump is working, since most of the time you can't hear it when you are in the drivers seat, is to turn on the key and go to the rear of the coach and set you remote start switch to rear. From there you can hear the pump by turning the coach on and off. (Note: be sure to return the switch to front when finished. Don't ask me how I know this.)

ECM 20amp Fuse was obvious and on top of the chassis batteries. It was in good shape. removed fuse and checked continuity on fuse and connection to the EMC via volt meter. Disconnected all chassis and house batteries checking voltage, 12.1 mol. Reconnected and ran generator to recharge.

Turn the ignition key switch to the On position/ Engine OFF. I think I left the key on in August? Tried both ways

Turn the cruise control ON/OFF switch to the OFF position.

Push the SET/COAST button and hold. Hold that position until the yellow lamp begins to flash.

The yellow lamp will flash in order to indicate a two digit flash code and

the SET/RESUME switch may be released.

When the fuel water separator filter was changed in Oct-2018 there was some foreign matter the RV man could not identify? After this service I drove the RV about 15 miles to storage? At the time the RV Man did not feel it was algae?

I miss stated , the yellow engine light briefly comes on then out when the key is turned. also, toggling the odometer/tach mileage tripmeter returns nothing, may be all zeros or 1888888 tripmeter 8888.

Ok, any puff of smoke from the exhaust while cranking? Not sure of your technical background but one simple check I would do on those engines; while cranking (requires two people) place a screwdriver or long something metal, while someone is cranking the engine put it against your ear, you should hear a ticking sound (usually very pronounced) from each injector, this will tell you they are attempting to fire (high pressure oil system is functioning). This will eliminate one portion, after that it just needs fuel and of course the electronics for injector timing to start.

Yes, under normal circumstance the check engine light will illuminate with key on then clear. I will try the screwdriver and listen for the ticking and also try and get the wiring schematic from Freightliner and or maybe Caterpillar? I have most or all the chassis wiring now but not the engine. I tried today at CAT but I could not find a full schematic of the engine wiring. I have a login to DTNA connect and it will pass me to caterpillar.

Another odd thing I noticed is I cannot reset the trip meter or get the odometer to switch between kw and miles. It will not display the current mileage but has showed all zeros or 1888888 for mile and 8888 for the trip meter.

My RV man met me today and he ran diagnostics without any success. Checking the wiring also. He was able to read the transmission info but nothing on the ECM. He then removed the ecm and our next step is for me to take it to Caterpillar tomorrow in Riverview, FL. The tech at caterpillar indicated they can try and read the flash and make a determination if it is good or not. I believe this to be the original ECM since there is writing on the back 8-3-01. My RV is a 2002.

Option 1 -- Where I store my RV there is a junker, 1999 monaco Freightliner. I have checked it out today and it is a caterpillar engine, the same as mine but older 1999, mine is a 2002. I am going to ask the tech tomorrow to confirm engine specifications since I have the VIN. So I am thinking about removing this 1999 ECM if the specs checkout and trying it. If it works why not? I know the storage man will let me have it for a very reasonable price. If this works then problem solved -- then "maybe" have caterpillar flash the correct mileage and check other settings at their site.

Caterpillar told me they will not program the ECM unless it is installed. He said it had to do with emissions? So buying a new/used/aftermarket means I either have the RV towed 50 miles or pay for a CAT Tech to come to the RV in Storage. This is upsetting.

Usually the difference is in the programming, like maximum speed for cruise control vs pedal could be different, exhaust brake function could be programmed different. Nothing that once its up and running the dealer couldn't customize to your preferences. This is all assuming they both are 3126E's.

When I worked at the dealership, I would keep a box of known good different modules, many times I would pull from the box to get something started in the parking lot and drive it into the building. If you have ever tried to push a motorhome you can understand why. Back in those years you could do that. Once the newer technology came along it wasn't so easy and eventually turned almost impossible as many differences came along and all of the modules were eventually coded as a group, once one "stranger" was introduced, nothing worked.

I have a friend that had a similar issue with is CaT motor from that year on a freightliner Chassis He did find a solution and if I can get Fred on the phone tonight Ill relay what his solution was. Not sure if it will help but at this point information is information.

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