Engine/Transmission (1998.5 - 2002) No buS

[darkhorse]

I'm not sure if this is the correct forum because I don't know what's causing this. I was driving home a few minutes ago & I heard three short chimes. My air bag, low fuel, ABS & check engine lights all came on. All 6 dash gauges went to zero & the odometer read No buS. The motor continues to run as if nothing happened. The key flip trick didn't bring up any codes but my Smarty pulled up a 1693 & a 1687. I restarted it several times. the motor sounds fine but the gauges are dead & the code won't clear. What gives??? Of immediate concern is if it is safe to drive like this. I'm scheduled to go over the hills & through the woods to Grandmothers house for Thanksgiving day tomorrow.

 

[blacksheepdiesel]

Check the electrical connector on the ecm, make sure it is tight and the pins have no corrosion. Also, check the plug on the VP44. Then check grounds for ecm.

Hope this helps.

Godspeed,
Trent

 

[darkhorse]

Thanks Trent. I'll look into it a first light.

 

[Road Dog]

A bus is a type of computer network and no bus means the computer in the instrument cluster can't communicate with the ECM. It could be as simple as a loose connector behind the cluster.

 

[darkhorse]

I've been spending some time reading in my service manual. I now know this is in the wrong forum. It's strictly an electronic problem having to do with the CCD data bus. (whatever that is ) I'm not at all sure how to precede. How does one check the CCD data bus connections at the instrument cluster? I hate to take this rig to the ******* :{ but I'm running low on ideas now. All the connections previously mentioned seem tight with no corrosion. The good news is that the truck runs fine. Even the cruise control works thought I have to guess about my speed. I can keep track of miles traveled on the over head computer.

 

[Sixpack]

My brother just went through this. It was as simple as a battery cable that had cracked at the connector to the battery. He replaced it and all is fine. Try checking the batteries, cables and all ground connections. Good luck,

Phil

 

[darkhorse]

Thanks, Phil. I'll be checking some of these things out tomorrow.

 

[Huff N Puff]

Any Computers On The Bus Can Bring The Bus Down

Here are a list of computers communicating on the bus:Injector pump module,ABS module,TCM,ECM,BCM,Instrument cluster,and overhead infomation module. If any one of these processors fail,can also short out the bus. Here is how I trouble shoot a bus problem. Disconnect one module at a time,to see if the bus recovers,Try it in this order ,ABS,Injector Pump module ,ECM,Over head info,Instrument cluster. If none recover the bus you have a shorted bus wire,or the TCM is at fault. You will need a scan tool if you disconnect the Instrument cluster,to test for a good bus signal.

 

[Huff N Puff]

I've been spending some time reading in my service manual. I now know this is in the wrong forum. It's strictly an electronic problem having to do with the CCD data bus. (whatever that is ) I'm not at all sure how to precede. How does one check the CCD data bus connections at the instrument cluster? I hate to take this rig to the ******* :{ but I'm running low on ideas now. All the connections previously mentioned seem tight with no corrosion. The good news is that the truck runs fine. Even the cruise control works thought I have to guess about my speed. I can keep track of miles traveled on the over head computer.

The info you provided,leads me to belive its the instrument cluster cause,cruise control, needs most of the other modules exept the instrument cluster,its probably a loose connection on the instument cluster possibly a cracked solder joint. try jiggling the connector on the back of the instrument cluster with the key on while watching the cluster see if it wakes up.

 

[darkhorse]

The info you provided,leads me to belive its the instrument cluster cause,cruise control, needs most of the other modules exept the instrument cluster,its probably a loose connection on the instument cluster possibly a cracked solder joint. try jiggling the connector on the back of the instrument cluster with the key on while watching the cluster see if it wakes up.

Thanks for the input, Huff. Is the connector accesible from under the dash? I did run the actuator test & got all 6 of the "900" codes. At the end the lights & gauges all went through their proper responses, so I assube the cluster itself is ok. The only scan tool I have is my Smarty so if I need a more sophisticated scan I'll have to take it somewhere.

 

[darkhorse]

The info you provided,leads me to belive its the instrument cluster jiggling the connector on the back of the instrument cluster with the key on while watching the cluster see if it wakes up.

You called it right Huff. I tried to get my hand on those plugs from under the dash but there was just no way. Today I pulled the bezel & the cluster. Just enough to unplug it then plugged it back in. BINGO! The gauge needles popped up. I don't know how the plug got loose but all's good now. Oo.

 

[Huff N Puff]

I think its going to be temporary,

You called it right Huff. I tried to get my hand on those plugs from under the dash but there was just no way. Today I pulled the bezel & the cluster. Just enough to unplug it then plugged it back in. BINGO! The gauge needles popped up. I don't know how the plug got loose but all's good now. Oo.

Cause its usually a solder joint where it enters the instument cluster,what we do is check it under a bright light and a magnifiying glass you can usually spot the minute fractures and resolder em with a small soldering iron. Might also be where the connector actually slides on to the connector,we use a needle to put a little tension on the female end,might also need a magnifiying glass for that operation.

 

[darkhorse]

Cause its usually a solder joint where it enters the instument cluster,what we do is check it under a bright light and a magnifiying glass you can usually spot the minute fractures and resolder em with a small soldering iron. Might also be where the connector actually slides on to the connector,we use a needle to put a little tension on the female end,might also need a magnifiying glass for that operation.

Would it be the right or left plug? Any particular pin to look at?