Class 2 Comm Failure
06-13-2012, 07:12 PM
#1
TECH Resident
Thread Starter
iTrader: (8)
Join Date: Dec 2004
Location: DFW
Posts: 796
Likes: 0
Received 0 Likes
on
0 Posts
Class 2 Comm Failure - ID'ed and repaired
Guys, (I've searched), I was driving my truck last week (after 9 months of no issues or modifications) when the instrument cluster in my Blazer showed that the truck had some kind of fault.
The fuel gauge went to empty, the water temp gauge went to cold, the Security light, Battery light, ABS light, Airbag light and seatbelt light all came on.
Tank was full, truck was at operating temps.
Drove it back home fine. Same power (
), no roughness in the engine.
Get it home and attempt to connect scanner, but it gets a "fails to connect" message on the AutoXray 6000.
4WD operates normally, but 4WD light on the IP does not illuminate.
Fuel econ/range/etc on the upper console does not display any information (class 2 serial data)
Auto power windows function normally, interior light stays on for a minute or so then shuts off, (both controlled by BCM so at least I know that's working.
It's got to be something very simple. It's running too damn good!
Grounds are all good and solid (everywhere)
I've found this identical problem on 4 other trucks in three forums (2 trucks in this one). No one posted a fix or repair suggestion in those respective threads.
Any suggestions?
The fuel gauge went to empty, the water temp gauge went to cold, the Security light, Battery light, ABS light, Airbag light and seatbelt light all came on.
Tank was full, truck was at operating temps.
Drove it back home fine. Same power (
), no roughness in the engine.Get it home and attempt to connect scanner, but it gets a "fails to connect" message on the AutoXray 6000.
4WD operates normally, but 4WD light on the IP does not illuminate.
Fuel econ/range/etc on the upper console does not display any information (class 2 serial data)
Auto power windows function normally, interior light stays on for a minute or so then shuts off, (both controlled by BCM so at least I know that's working.
It's got to be something very simple. It's running too damn good!
Grounds are all good and solid (everywhere)
I've found this identical problem on 4 other trucks in three forums (2 trucks in this one). No one posted a fix or repair suggestion in those respective threads.
Any suggestions?
Last edited by philntx; 06-29-2012 at 05:40 PM.
06-13-2012, 11:38 PM
#2
TECH Veteran
iTrader: (36)
Theres a module or connection problem on the buss that's killing communication. You have to find the code being stored in several modules then follow the comm buss trouble shooting until is figured out. I never done it without a tech 2 so I can assume with non gm tools it will be a bitch to do in your driveway.
What truck is this on?
What truck is this on?
06-29-2012, 05:40 PM
#6
TECH Resident
Thread Starter
iTrader: (8)
Join Date: Dec 2004
Location: DFW
Posts: 796
Likes: 0
Received 0 Likes
on
0 Posts
Fixed
Found the problem after tracing every class 2 data wire. Serial data module for the drivers door has an internal fault. Un-plug it and the dash goes back to normal and the tech2 can communicate with the truck.
Should be back in business on Monday.
Should be back in business on Monday.
06-29-2012, 05:41 PM
#7
TECH Resident
Thread Starter
iTrader: (8)
Join Date: Dec 2004
Location: DFW
Posts: 796
Likes: 0
Received 0 Likes
on
0 Posts
Theres a module or connection problem on the buss that's killing communication. You have to find the code being stored in several modules then follow the comm buss trouble shooting until is figured out. I never done it without a tech 2 so I can assume with non gm tools it will be a bitch to do in your driveway.
Thread
Thread Starter
Forum
Replies
Last Post
FlowmasterMufflers
Cummins Diesel Performance
0
08-17-2015 04:44 PM
carid
Ford / Lincoln General Discussion
0
07-24-2015 05:00 AM
