Long story, but I installed a K&N air filter kit but was missing a ECU/TCU plate, so left the bottom of the stock airbox that holds them in place and installed the filter and piping and all was fine.
Today I was trying to take that bottom piece out but it was stuck, so the ECU flung out of the holder and landed right smack on top of a very thick red wire connector that looks to be hooked to the ABS and started sparking like crazy (The outer metal heatsink of the ECU was sitting right on top) . Now the car doesn't start at all, and the information center says low fuel (ithe car is full, I just filled it up yesterday), it says service stability control system and service traction control system and cycles through that. (So seems like the ECU is completely fried. I checked all the fuses and they appear to be fine.
Anybody know a way to diagnose if it is the ECU or the wiring that got fried?
The negative terminal is completely stuck on, I guess I'll have to spray some WD40 to try, but for the info center saying all that stuff I think the ECU is fried, but I'm hoping it is not the ECU and the whole wiring harness too.
if you did not blow any fuses and it stopped sparking before your battery was completely discharged, you melted at least one wire. The computer might also be fried, but i would start by checking all the wiring harnesses, including/especially grounds. Sorry to say; it's going to be a long hard, likely expensive solution.
__________________ -Douglas
"Fear is a feeling, not a barrier." -me, 1998.
2006 Impy SS, LS4 transportation appliance 68K (Ultra-flo's, spacer, CQL rockers, etc).
1996 Fleetwood Brougham LT1 99.99K.
1995 Caprice 9c1 LT1, 238K (in more than one piece)
1985 Honda VF1100S, for those days when you just have to crank off an 11 second quarter-mile. 22K
if you did not blow any fuses and it stopped sparking before your battery was completely discharged, you melted at least one wire. The computer might also be fried, but i would start by checking all the wiring harnesses, including/especially grounds. Sorry to say; it's going to be a long hard, likely expensive solution.
Anybody know where I could get a wiring schematic of the connectors to the ECU? Maybe I can use an OHM meter to see which wires are melted.
Damn. Disconnect the negative before working on electrical stuff.
Is the battery just dead?
Everything works inside the car, the AC, radio, dash lights up, keyless entry works ETC. I don`t think the battery is dead. I think when all the sparks were happening, something really bad happened, I`m just hoping it is ONLY the god damn ECU and nopt wiring or something that would be almost impossible to diagnose (other than replacing this/that) Until it works. I thought the shell of the ECU would be protected, but the heat sink just transferred all that voltage through the whole damn ECU. The info center saying that the traction and stability control system needs servicing might be from the ECU damamging the part that it contacted (I'm guessing the ABS pump) It's on the driver side of the block and is bolted on the block, it is a cylinder shape and a little thinner then a pop can. The wire that the ECU landed on was a connector that loops around a bolt and held on with a nut on that part I was describing. It is a very thick red wire.
The anti theft stuff might screw you over when you try to hook it up. This is assuming it's just the ecm. Should be able to find an ecm on ebay for like 50 bucks, but it probably won't be programmed right so yea... E67 would be the newer ones I think.
The anti theft stuff might screw you over when you try to hook it up. This is assuming it's just the ecm. Should be able to find an ecm on ebay for like 50 bucks, but it probably won't be programmed right so yea... E67 would be the newer ones I think.
I think I might have to buy a second car for the time this might take to fix I have a bad feeling that even if I buy an ECU, something still won't work. I hope it didn't like fry everything in the engine bay that is electronic.
The anti theft stuff might screw you over when you try to hook it up. This is assuming it's just the ecm. Should be able to find an ecm on ebay for like 50 bucks, but it probably won't be programmed right so yea... E67 would be the newer ones I think.
I disconnected the battery and disconnected the 3 connectors off the ECU, looked at the pins, and the middle connector on the ECU has a whole bunch of small pins that are bronze and one larger longer pin (also bronze) The larger longer pin has black marks on the part closest to the board of the ECU and smells kind of like a firecracker, on the connector side it is also dark and has black powder, all the other pins on the rest of the ECU and other two connectors are fine.
If I get a used ECU, do I have to take it to a GM dealer with my cars VIN and pay them to program it? (Just to see if that even fixes the problem?) Could they do it without the car being there?
the computers are pretty tough on these things and the arc would have been on the case. therefore mostly heat damage if any to the electronic bits. I would carefully clean the burn marks off the pin with some very, very fine sandpaper and plug it back in before you start looking for a one.
__________________ -Douglas
"Fear is a feeling, not a barrier." -me, 1998.
2006 Impy SS, LS4 transportation appliance 68K (Ultra-flo's, spacer, CQL rockers, etc).
1996 Fleetwood Brougham LT1 99.99K.
1995 Caprice 9c1 LT1, 238K (in more than one piece)
1985 Honda VF1100S, for those days when you just have to crank off an 11 second quarter-mile. 22K
the computers are pretty tough on these things and the arc would have been on the case. therefore mostly heat damage if any to the electronic bits. I would carefully clean the burn marks off the pin with some very, very fine sandpaper and plug it back in before you start looking for a one.
My neighbours relative (Has his own shop) came by today to take a look at the ecu and wire. The ECU landed on the live power wire to the starter (Its a small ass starter on these cars) The pin in the ECU that was fried is from one of the main ground wires from the harness. So the ECU is completely fried. The connector wire is okay. I tested it with an OHM meter and it shows the wire is fine, the actual little bronze plug that the pin from the new (replaced ECU I will have to buy) goes into will have to be replaced because the plastic part around it was burned so it will not make a perfect tight fit (vibration from driving can damage the new replacement ECU if this is the case) So I need to buy one of the connectors to take a plug from and somehow pull the damaged one out and solder it in. I doubt the dealer would sell this seperately.
I got my used ECM from an '06 GMC Envoy Denali that has the same PCM and a 5.3L VORTEC. The ECM has the same service number.
Should I try to start the car with this ECM? I want to avoid the tow truck cost of getting the car to the dealer to get it flashed to the '05 GP GXP but wondering if trying to start the car can do any harm (assuming it were to work) If I use my cars TCU I would think that the only differences are the fuel maps that give the Envoy torque at a lower RPM and slightly less HP at lower RPM and my TCU would know what to control for the tranny. Another thing is I'm not sure if this ECM came out of an AWD Denali, so not sure if that will make a difference either.
Please if anyone has experience with this LMK.
Last edited by highonpsi; 06-19-2009 at 06:43 PM..
I got my used ECM from an '06 GMC Envoy Denali that has the same 5.3L LS4. It has the same service number.
Should I try to start the car with this ECM? I want to avoid the tow truck cost of getting the car to the dealer to get it flashed to the '05 GP GXP but wondering if trying to start the car can do any harm (assuming it were to work) If I use my cars TCU I would think that the only differences are the fuel maps that give the Envoy torque at a lower RPM and slightly less HP at lower RPM and my TCU would know what to control for the tranny. Another thing is I'm not sure if this ECM came out of an AWD Denali, so not sure if that will make a difference either.
Please if anyone has experience with this LMK.
I could be wrong, but I thought the 5.3 in the trucks are Vortek, not an LS4. They may share the same programing I don't know. Are the part numbers the same?
The LS4 is not the 5.3 from the trucks. The only things that have LS4's are 05-08 Pontiac Grand Prix GXP's, 06-07 Chevrolet Monte Carlo SS's, 06-09 Impala SS's, and i think 08-09 Buick Lacrosse Supers.
That engine is a 5.3 liter Iron Block...the LS4 is a 5.3 Aluminum Block derived from the LS1/LS6/LS2.
WHY DO PEOPLE THINK THEY ARE THE SAME ENGINE...... Do your homework....
__________________ 2007 Monte Carlo SS Flipped Motor Mount......For Now
Silverstone Metallic (No Stripes)
The LS4 is not the 5.3 from the trucks. The only things that have LS4's are 05-08 Pontiac Grand Prix GXP's, 06-07 Chevrolet Monte Carlo SS's, 06-09 Impala SS's, and i think 08-09 Buick Lacrosse Supers.
That engine is a 5.3 liter Iron Block...the LS4 is a 5.3 Aluminum Block derived from the LS1/LS6/LS2.
WHY DO PEOPLE THINK THEY ARE THE SAME ENGINE...... Do your homework....
No need to be rude, the programming could be the same. Lets give him the benefit of the doubt here. Good luck....
Urgent help needed 
I have a bad feeling that even if I buy an ECU, something still won't work. I hope it didn't like fry everything in the engine bay that is electronic.
Do your homework....
