Last week I posted that the 1-4 shift light came on and pretty much locked up every gear except 4 and 6. Could not get the car in gear except for one of those. Check engine light came on when this happened. Called Onstar, they diagnosed that 1-4 shift module was faulty and to take it to dealer. With me being the mechanical genius I am, I disconnected the negative battery terminal for a few minutes, reconnected and light went out.

This morning I drove the car to work. Shifting in slow traffic, the 1-4 shift light comes on, and locks all the gears except 4 and 6. Even when I stopped, only 4 and 6 were the only ones the shifter would fall into. Starting in 4th required alot of rpm's let me tell you! After accelerating to 35-40mph or after a minute or so, it seems the computer kicked back in and allowed all gears to be accessed. I know that when the 1-4 light kicks on it requires a shift to 4 but then you can immediately acces other gears. I wasnt allowed any gears for a minute or so or until I reached 35-40 mph.

The question is, has anyone else had this issue, should I really take it to the dealer who will say they cannot do anything unless thet can duplicate it, and will there be a code they can pull even though Onstart now says that no problems exist in their diagnostic probes and no codes appear in the DIC.

By the way, on start up, the check engine light is the first to come on then the rest on the panel illuminate as usual then go out. I think they all used to illuminate at the same time and shut off at the same time.

Will the shift eliminator resistor sold by vendors on here eliminate the problem I have or should it really be taken to a dealer? I really ahte to take to a dealer and risk panel breaks, joy rides and scratches! Thanks for any advice, hopefully the pros here can help!

 

I don't have an answer for you, but taken off in 4th gear to many times is not a good idea.

TRR

 

My check engine light usually is the first light to come on too, before the other ones. It's always been this way though and my C6 has never had a problem.

What I would recommend is taking the car to the dealer and let them replace the faulty CAGS solenoid if that is the problem. I would also install the eliminator or tune out CAGS in the PCM and be done with it.

I used my Diablosport Predator to disable CAGS completely and the only time I see the 1->4 light is when I first start the engine. It's been smooth sailing for almost two years now.

 

Well I would take it to the dealer but make a appt . so that you can be there for any test driving during diag.

 

IMO don't be so paranoid about taking the car to the dealership. I'd politely explain your concerns to the service advisor and then let them fix the problem. After the problem is fixed, remove the skip-shift feature with a GAGS eliminator or have it tuned out. If you're concerned that altered tuning (even something so minor) might jeopardize your warranty...go with the GAGS eliminator.

They will have to test drive the car to replicate the fault. If you want, tell them you want to go-along on any test drives. You tend to read more about dealership problems here on the forum. In truth, problems are the exception and not the rule. Most of the time the dealership will muddle-through and get the job done.

Get your car fixed before the problem causes an accident or causes further damage.

 

Great advice and well stated.

 

Don't disconnect the darn battery! That erases the code held in "history". Even if the light goes out on the dash, the ECM remembers and tracks codes. They will know what is happening and happened by the history in the ECM. Take it to the dealer and get it corrected.


Elmer

 

My 1-4 shift light almost never comes on, thanks to my right foot!!

 

This sounds like a mechanical problem. The skip-shift solenoid should just lock-out 2nd gear (the shop manual claims 2nd and 3rd, but I remember 3rd was accessible). According to your description, though, you couldn't access 1st, 2nd, 3rd or 5th. I assume the problem persists even after the 1-4 light goes out? Something in there is stuck/bent/jammed.

The shift eliminator resistor just fools the computer into thinking it's connected to the solenoid when it really isn't. That way it doesn't set the CEL. It's the actual unplugging of the solenoid that defeats the skip-shift, not the resistor. The computer continues to do its thing, illuminating the 1-4 light, blissfully unaware that it isn't actually connected to the transmission.

I appreciate your reluctance to visit the dealer, but you probably should.