DDEC II

Cary and Don · December 26, 2013, 02:22:59 PM

We are stumped here. If you hook up the pro link to the diagnostic plug and the pro link says "No modules found", is the box dead? There is power to the six way connector. The engine cranks but doesn't even try to start. It has fuel in the filter.

Now for the confession. I, Cary, did a really dumb thing. You know, like not checking the battery cables real careful when hooking up the 24v system? Like when both cables were red? Thinking it wasn't very happy about being hooked up backwards, even though it was just for a minute. Didn't even turn on the run switch on the dash.

So, HELP

If it's dead, anybody have one?

Cary

robertglines1 · December 26, 2013, 02:45:56 PM

you should be fuse protected.. look for it. would be step #1 also make sure connector is good= not corroded. these are two most common problems.. fuse would be most likely in your case.. bob

luvrbus · December 26, 2013, 02:52:01 PM

Maybe you got lucky and it just blew the 2 -15 amp fuse going to each head the DDEC 11 is 12 volt only and they don't like 24 volts unfortunately the fuse don't recognize volts only amps

good luck

Iceni John · December 26, 2013, 03:19:34 PM

Do the CEL and SEL both illuminate for a few seconds after turning the key to the Run position? In addition to the two 15A fuses for the injectors, do you have a third 15A fuse for the DDEC relay? My relay is up front in the main electrical panel, but all three fuses are in the engine room.

John

Cary and Don · December 26, 2013, 04:38:43 PM

The two fuses inline to the injectors look fine. There was another inline fuse in a harness in the same area and it appeared ok also. There doesn't seem to be any sel cel sto lights. There is a button to push for check ddec. I found a breaker in a panel box that was for the ddec and it wasn't blown. When you turn on the run switch the check engine light comes on and then goes out after about five seconds. Pretty sure the check engine light flashes the codes. This is in the Neoplan by the way.

Cary

robertglines1 · December 26, 2013, 05:05:43 PM

When all else fails check fuse holders and continuity of fuses.. never assume anything.. do wish you the best..

luvrbus · December 26, 2013, 05:16:26 PM

No codes should be flashing unless you push the override switch active codes are flashed from stop engine light the inactive codes are flashed through the check engine light I presume you have a diagnostic request switch ?

niles500 · December 26, 2013, 06:58:54 PM

Don't know your system as to what is 12 and what is 24 volt, but if you have vanners there is a circuit breaker reset - HTH

Jon · December 27, 2013, 03:38:52 AM

I don't know about other coaches, but when a Prevost owner swaps out chassis batteries and miswires them the end result often is the DDEC is not getting 12 volts and therefore the coach will not start.

My first place to look would be to verify DDEC is getting power where it is supposed to. A Prevost has multiple power sources feeding DDEC.

luvrbus · December 27, 2013, 04:08:02 AM

From the 111 on the DCEC's don't care if it is 12 or 24v supply Cary says it has power check the ground now

Jon · December 27, 2013, 05:17:33 AM

But isn't DDEC II a 12 volt system?

luvrbus · December 27, 2013, 05:23:16 AM

Yea Jon the DDEC 11 is 12 volt only remember not long ago here the guy working on the Prevost hooked the DDEC 11 up to 24 volts and cost him a new ECM and then he had electronic transmission problems I wonder if he ever got that bus on the road ?

Boomer · December 27, 2013, 08:59:18 AM

On a DDECII it ain't gonna start if the voltage drops down around 12.2, they are fussy that way. Get your batteries up in the 13V range and see if it starts.

Cary and Don · December 27, 2013, 09:13:45 AM

We will check the fuses and holders again. We will check the vanner. The power going to the ddec is 12.8 volts. It turns over really fast. We will check the codes by Clifford's directions. It has a ddec diagnostic button. Maybe, will try and crank it with the override switch pushed. The transmission is 12 volt. There are two breakers in the battery compartment that say they feed the injectors that had blown. But they aren't blowing anymore.

Cary

B_K · December 27, 2013, 12:54:15 PM

Don't just check "visually" on the fuses. Use an ohm meter an make sue you are getting close to zero ohms thru the fuses & holders.

While you have the meter out go ahead and check to see that you are getting 12+V to the ECM and the both of the injector wires.

I've seen and heard many times the fuses are good they look fine when they in fact were bad when checking with a meter.

BK