cluster doesn't allow codes to be read

My speedo cluster seem to have a very strange affect on reading any codes.
I found it by take everything out to check for a burnt wire or something but I did not. I showed a friend what it was doing and there was codes. camsensor ckt malf/range or something to that effect. The cluster works fine sort of (no codes being read) but has anybody had this problem before????????????:popcorn:

Not quite sure what the problem is.
Try to give us a little more info.
Year make and model and mileage and engine.
What code no are you getting?
Are you trying to read codes on a scanner or from cluster?

Well this is the thing, when I plug in the scanner to read the codes it comes back data link error. I thought it had a bad short in the wires but I did not find a bad wire anywere. So with that in mind I thought maybe the ecm, bought one replaced it and nope that wasn't the case. So I went back to my orignal thought wires.... then when I showed a buddy what it was doing after I pulled every thing around the steering column it read the codes??? I then played with the wires and cluster one by one sysmaticly and came to the conculsion that when the cluster is pluged in it wont read codes, and when its out it does???????

WHAT YEAR MAKE AND MODEL AND ENGINE AND TRANSMISSION AND MILEAGE?
Check the wiring to the diagnostic connector.

1997 chevy k1500 4x4 at 103k.
yes I did check the wiring on the link connector. fine, no broken, pulled or burnt wire.

But did you check for power and ground and where all the wires connect to.
Make sure it has power and all grounds.
And all wires are good back to the pcm.
What codes are you getting when it reads codes

For a pin out on the OBD11 connector.
http://www.troublecodes.net/OBD2/

Well the code comes out as P0336 and I replaced the cam senor in the dist. cap... Yes on the wires good power and grounds, so were the connections.

It is strange but at least you found what to unplug to get codes.
Does the scanner read out all modules and data good when the dash is unpluged?

sorry for the time. but yes and everything seems to run find when I replace the cam sensor. two borge warner and one oe part from chevy. Then ten minutes latter the code pops up.

We need the engine sise?
Code 336 is a crankshaft circuit sensor code on a 5.7 V8!!
Are you working on the right sensor?

We need the engine sise?
Code 336 is a crankshaft circuit sensor code on a 5.7 V8!!
Are you working on the right sensor? Yes it is a 5.7 v8

Code 336 is a crankshaft position sensor circuit problem.
Good luck MT