Service 4wd Scan Codes

[hpracing10]

Well, this morning I visited the dealership to find out why i was getting the service 4wd message on my truck. Came back with 10, YES 10 different codes that were coming from the transfer case he said. Anyone know a good website I can go to that will translate all the codes and help me pinpoint what needs to be replaced? Here is a list of the codes that he pulled from my truck:

 

BO790-transfer case nuetral indicator circuit malfunction

CO550-ECU malfunction

CO379-front axle control circuit malfunction

CO374-general system malfunction

CO359-discrete output circuit malfunction

CO306-motor A/B circuit malfunction

CO300-rear propshaft speed sensor malfunction

U1301-class 2 communication circuit low volts

B2725-mode switch circuit malfunction

U1000-class 2 data link malfunction

 

Anyone have any ideas? He told me that 9.9 times out of 10 it is just the push button switch that is bad, but when that switch is bad only about 2-3 codes are thrown, not 10. He said that putting in a new push button switch panel would probobly fix most of it but with that many codes it could be a lot of things. I plan on doing the fix myself just needed GM to check the codes for me. So if anyone has any experience with these same codes, or knows a good website I can visit to translate these, please let me know! Thanks

[hpracing10]

I think I will start with replacing the switch. Anyone know where I can find a new switch? The part # on the back of my switch is 15164520. I type that into the search on www.gmpartsdirect.com and it says no results found. Help is appreciated! thanks

[Pig Hunter]

 

 

I think I will start with replacing the switch. Anyone know where I can find a new switch? The part # on the back of my switch is 15164520. I type that into the search on www.gmpartsdirect.com and it says no results found. Help is appreciated! thanks

I just bought one on ebay for $55.00, didn't solve the problem on my '05, but I think the switch may be the issue on the '03 and back. Had one, same problem, switch was the fix, don't know on the codes. Try clearing the codes, then turn on the key, 1st code should be your booger.

[lvlagnum]

I had an 03 Silverado 1500 EC Z-71 and I got the "SERVICE 4 WHEEL DRIVE" message on the DIC at about a year and 12,000KM. I have no idea what codes my truck was throwing. The dealership did a reflash under warranty and it was still fine when I traded it in a year ago. On my truck, the switch was fine. But I understand some of them do need replacing from time-to-time. I hope this information helps.

 

Cheers, lvlagnum.

[GeneratorPower]

I had this same problem on a 2006 Suburban. Turned out to be a broken "encoder motor" which apparently is responsible for shifting 4WD modes. Cost me $435, labor included, at my local 4WD shop to have it replaced.

 

Symptoms were:

 

Mysteriously in the wrong 4WD mode when I return to the truck after parking for a few minutes.

 

Service 4WD message periodically.

 

Control buttons all go completely dark.

 

Control button stays lighted in 2WD mode but system refuses to switch modes (stuck in 2WD).

 

The encoder motor seems to have fixed all this.

[Pig Hunter]

I had this same problem on a 2006 Suburban. Turned out to be a broken "encoder motor" which apparently is responsible for shifting 4WD modes. Cost me $435, labor included, at my local 4WD shop to have it replaced.

 

Symptoms were:

 

Mysteriously in the wrong 4WD mode when I return to the truck after parking for a few minutes.

 

Service 4WD message periodically.

 

Control buttons all go completely dark.

 

Control button stays lighted in 2WD mode but system refuses to switch modes (stuck in 2WD).

 

The encoder motor seems to have fixed all this.

[Pig Hunter]

Mine has a C0327 code. However, I had the same thing fixed under warranty at 33K, now have 122k. Went to talk to service manager at dealership and had something interesting happen. Driving in to the service department hit a couple of tall speed bumps, came out to leave and no service message, hit 1st bump message came on, after hitting 2nd bump, pulled over, shut down and restarted. No message! Been off since then, going to check all electrical connections this weekend. By the way, service manager was not cooperative, quoted $600 to fix the problem. I already bought a new sensor, but am thinking to keep it as a backup, if ground or connection is the problem.