p0650 & p0281 I am stumped! 2004 slt z71 4x4 5.3

[breeze.12]

have these 2 codes. the 281 is a soft code or maybe a history code, but the 650 is hard fault, cannot be erased, service light on all the time. cleaned the grounds, checked the fuses. I am wondering if something in the cluster itself is bad. some on diesel forum had problems with starter relay causing code, I hope someone has some ideas thanks ( po650 is malfuction indicator lamp), and the 281 seems to be a fault in #7 cylinder not concerned with this one, it cleared and hasnt returned thanks





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[usmcchevy]

To the site. The only time I have seen P0650 was a bad ground on the back of the engine and that one had LOTs of codes set. This might help.

http://www.ls2.com/boggs/dtcs/DTC%20P0650.htm

[clinebarger]

P0650 (Malfunction Indicator Lamp circuit malfunction)
Possible Causes
MIL control circuit is open, shorted to ground or shorted to voltage
MIL control Ignition circuit is open in the Instrument Cluster
MIL (the lamp) has failed
Instrument Cluster (IPC) has failed
PCM has failed

Because the MIL lamp stays on all time, I would bet the MIL wire is shorted to ground between the PCM & IPC.
If you have a Volt/Ohm meter & know how to use it, Ill help you fix it.

[breeze.12]

hi and thanks for the help, yes I do have all the testers and ohm meters required. I have fixed the stepper motor in the cluster service light is on all the time. when it comes to tracking down shorts or grounded wires it can be a real pain. so yes, if you have a way to walk me through some test that would be great. thanks again. just tell me where to start.

[clinebarger]

Remove the cluster, Pin A1 is MIL control, Pins B12 & A12 are grounds. Check for continuity between the MIL control & grounds If there is continuity, The short to ground is in the cluster.
If no continuity in the cluster, Check the cluster plug the same way.

These connector veiws are "looking at the plug" so when your looking at the cluster pins it will be mirrored.

[breeze.12]

Ill try it right now thanks!! just checked it?????? continuity between A1 AND B12 ALSO B1 AND B12 OUT OF CURIOSITY CHECKED THE HARNESS AND ALSO THE SAME THERE. DOES THAT SOUND CORRECT?

[breeze.12]

Also usmcchevy thanks for the diagram. Will start the process.

[clinebarger]

Originally Posted by breeze.12

Ill try it right now thanks!! just checked it?????? continuity between A1 AND B12 ALSO B1 AND B12 OUT OF CURIOSITY CHECKED THE HARNESS AND ALSO THE SAME THERE. DOES THAT SOUND CORRECT?

No, It doesnt? Did you remove the cluster from the truck (disconnect the harness) & test it separately?

[breeze.12]

yes, cluster is out of truck. whoops, i just went out and checked it again. it appears to have continuity between a1 and b12 only. in the harness the ohm meter goes about 60 to 70% up but not all the way. so that mean the cluster? if so is there any way of fixing that? while replacing the stepper motor I saw some solder joints that appeared to connect 2 connections. just didnt look right. proably would be kinda hard to find a ground problem in the cluster huh? thanks

[clinebarger]

Originally Posted by breeze.12

yes, cluster is out of truck. whoops, i just went out and checked it again. it appears to have continuity between a1 and b12 only. in the harness the ohm meter goes about 60 to 70% up but not all the way. so that mean the cluster? if so is there any way of fixing that? while replacing the stepper motor I saw some solder joints that appeared to connect 2 connections. just didnt look right. proably would be kinda hard to find a ground problem in the cluster huh? thanks

The problem occurred after replacing the stepper motors Right? Ive never replaced them myself, Did you have to solder the stepper motors in? Maybe you dropped some solder on the curcuit board.

[breeze.12]

no.. p0650 code was there from the go, I just hoped fixing the stepper motor would take care of the code, but it only fixed the non working speedo. does what Ive described on the continuity, for sure, sound like a bad cluster? if so, and if I cant track it down within the cluster, probably just send it off to be repaired. just want to make sure thats it, and not somewhere from the harness to the pcm, or something else. but I definetely have continuity between the 2 points I stated, so if the problem is for sure in cluster, and I cant find and fix it myself, my choices are probably very limited. thanks if you think of anything else please let me know before I send this off for repair.

[truckdude239]

Btw advance auto part sells these clusters made reman by dorman with a lifetime warranty, they run 299-350 dollar depending on which one it is

[truckdude239]

if you are probing the harness with the cluster out and a1 and b12 have a reading then either the harness has a short in it or the pcm does. i'd say unplug the pcm and then see if you have a reading for ground ohms if you don;t i'd say the pcm is at fault

[breeze.12]

thanks, the direct continuity (between a1 and b12) is in the cluster, not in the harness. this must be a difficult problem. I was hoping that maybe someone had fixed certain solder joints or knew of where these shorts in the cluster may occur as to be able to repair it myself, or what to look for to figure it out and repair. as to not have to send it in. thanks again

[clinebarger]

I just tested a "Known Good" 02 LS1 F-body harness & computer....It has a pretty low resistance reading between the MIL & ground...So I would call your PCM & harness good. There is no info on what the MIL driver in the PCM does with no power going to it, So I had to check

Ive never ran across this problem in a cluster before, You might do more harm than good messing with the curcuit board, But it might be somthing simple, Maybe someone will chime in on this.

Heres my readings of the harness & PCM connected, It read "open" or "infinite" with the PCM unplugged.

[breeze.12]

sorry just got the post thanks for the reading , ill recheck reading with pcm both ways. unless someone else chimes in Ill probably sen off cluster before messing with it thanks again