So the truck is giving the No bus code mostly in the afternoon when outside temps are higher the truck dies. It will usually restart a couple of minutes after this happens but during it shows No bus. I'm 90% sure its the ECU.

My question is, are there ECUs that are interchangeable with a 1999 1500 sport with the 5.9 V8 auto and does the ECU have to be flashed to the truck in order for the truck to start and run?

I'm hoping to buy one for $35 from a junk yard to see if the problem is fixed and if so buy a remand one for the truck permanently.

Thanks all!

 

PCM from 98-99, same engine and trans, will work. Doesn't need to be flashed for the engine to run/trans to shift. DOES need the vin updated to turn off the ABS/Brake/SRS lites. (I think)

if the junkyard PCM fixes the problem, just get the vin updated, (dealership probably, maybe some local shop with a GOOD scan tool) and call it a day. Don't bother getting a reman. (and in any event, avoid auto computer exchange like the plague, their reputation is horrid.)

 

Thx for the info and headsup. The reason I'm going for a reman and holding onto the junk yard one is because It's $100 for a reflash at the dealer and to me not worth spending that on a used unit that may do the same thing right around the corner.

 

Before you go spending money on a new PCM, for the hell of it pull out you gauge cluster and check it out. Ya it sounds crazy but it happened to me. I'd be drivin along and out of no where I'd get a "No Bus" and I'd loose my gauges and they wouldn't come back unless I shut off the truck and restarted it. After pulling my gauge cluster out I had found that there were some screws missing that hold it in and some wires were loose. Tightened everything back up and never had the problem again.

 

Well the truck is completely shutting down when this happens as well. We are going to warm up the ECU with a heat gun (not burn it with the gun, lol) to see if we can get it to happen.

 

Ya I was told that what usually happens with these ECMs is that over time as they get brittle and heat gets to them, they start to warp and crack.

 

Anyone know of a good company for a fair price that sells the remand ECUs? I've been looking at the ones on Rockauto but haven't found any reviews on them.

 

You need to check all the simple stuff before you swap the ecm.

Common cause of No Bus is the large connector in the power distribution center, large white plug, pull it off and spray with electronic cleaner(Disconnect the Battery!)

Do same for the ecm connectors

Remove all under hood ground cables, sand down to bare metal, reattach

 

I'll go a head and try all that first, thx! Do you also recommend applying dielectric grease after cleaning them?

 

Can't hurt. Just make sure they make good contact.