A few weeks ago while driving, about every warning possible popped up in the DIC. REP, ABS, TPMS etc. And the right door lock and window quit working. Car continued to run fine.
Pulled the right door wires out, cleaned the connectors, tweaked a couple of suspect pins and taped the wires to keep that bare one in the clear sleeve off the chassis.

All was well until today. Sitting at a stop light and the car just dies. Start it back up, it ran, but REP back on the DIC and this time it was real. I could manage about 5 mph. Shut off, restarted, same. Essentially no throttle.

Pile of codes of course, but only 1 PCM code, P1221 which is TPS1 not agreeing with TPS2 essentially.

I had the TB off prior while replacing intake gaskets. It's the LS2 90mm unit so I have a conversion harness in the system.

I cleared all the codes, unplugged and replugged the TB harness and of course it ran fine.

Now I wonder when the next gremlin will show up?

Also during this time frame my fob keeps losing sync

I'm good with the electrical stuff, but it sure would be nice to actually find the smoking gun!

I have to mention that the car now lives outside, and did get water on the pass floor during a large T-storm a couple of weeks ago. I saw now incursion into the BCM area......

Suggestions?

I will start chasing grounds, although I went through most of them last summer. I may have missed some,

Ron

 

A ground would be my first thought too. Since it's random and affecting multiple systems that don't necessarily have any interaction, it almost has to be a ground.

 

I think it's just pissed off at me for leaving it outside in the rain.
:-)
My research says I also need to suspect the throttle body and TAC module. The ABS codes get thrown because of the TPS code.
What a pain.

There is something to be said for the much simpler cable driven throttle!

Ron

 

Here is a link to a great listing on grounds and what is "landed" there. Might help you to see what may be common to your issues.

Have your ever replaced your ignition switch( electrical portion)?

As far as other suggestions, you have not given us all the codes to evaluate, just the ones you thought were important. Clear everything and the next time you have an issue give us what you find. Also pull them before you turn the ignition off and include H or C info.

http://forums.corvetteforum.com/c5-t...locations.html

 

Thanks. I have not replaced/repaired the ign switch. I should do that.
Also have the dim HVAC issue. As well as a code for a shorted inside temp sensor for the HVAC. B0337.

The rest were the typ hvac and radio comm codes.

I'll write them all down next time.

I have the factory manuals and will look to see where the TAC and TPS grounds are to start with.

 

I suspect a serial bus issue probably was at work too.

 

Many of those symptoms can be caused by a faulty ignition switch.

I went through two ignition switches over a two year period. Symptoms included dying at a stop sign but OK restart, crank, no start but crank and start OK on second try or crank and start with multiple codes, crank and start but with reduced power. Crank no start but crank, start and OK power on second try but check engine light.

Codes included low voltage, service traction control system, door codes, DIC and instrument cluster flashing on and off.

Before changing ignition switch though, I would be sure ALL grounds are clean and tight and that the battery is test confirmed good with the side terminals clean and tightened to 11 foot pounds.

 

Of course it's all working perfectly right now.....

 

Do the grounds and inspect the ignition switch and replace it or clean the contacts if they look burned. YOUR issue WILL come back if you do nothing.

 

Duh....really?
I'd like it to come back so I can get a complete list of the error codes.

I have a turbo 5.3 Nova to work on, and just finished a cyl head upgrade on our 355 S10.
So I've been busy.

I'll do the ground inspection tomorrow and get started on the ign and dim hvac as well.

Somewhere I have Curlee's link to the ign switch repair.

Ron

 

Here is some Bill info:

http://forums.corvetteforum.com/1568186703-post64.html

http://forums.corvetteforum.com/c5-t...ch-repair.html

 

Thank you!

Ron

 

Ok

I pulled the console out as well as the knee bolster.

Fixed the dim HVAC.
Nice write up on that!
At the same time, this fixed the B0337 code for the inside temp sensor. The sensor wires had gotten pinched. It was obvious I wasn't the first person to have this all apart.
Removed the ign switch and followed Curlee's steps. The contacts were quite pitted.
And finally cleaned the batt terminals. I hate side term batts!

Tomorrow I'll remove the cover and have a look at the PCM and TAC module. Then figure out via the service manual where the grounds are located for the TAC system.

Whew!

 

Hi Ron,
From my experience you found your main electrical problem/smoking gun which is the wires(inside the black accordion style grommet) between the drivers door and the body. This electrical short can popup at any time, and can go away on its own or by simply closing/slamming your drivers door. The first time I had this problem was December of 2006, I read up on this problem in the forum and confirmed it was those dreaded wires. The way I confirmed the problem was by simply grabbing and twisting that black accordion the next time everything went haywire and sure enough the problem went away. Sometimes the problem doesn't happen again for years. In my experience a good twisting lasts years. When it happened once before I tried to clean the blue connector, make sure all connections were tight, cut out and replaced some suspect wires, taped all the wires up tight and put 2 ft. of split-duct around the wires. I thought I had that problem licked but it happened again a few years later, so I simply twisted those wires and that's the fix. In 12 years this problem popped up maybe 6 times. I hope this helps you because I haven't forgotten when you offered your help to me when I was living in Oregon.

 

I remember, you had the air check valve problem.
I did the whole door thing and no love. When that wa going on, I got the reduced power message, but the car ran fine and the pass door was dead.
Door had been fine since, but this last episode the car shut off. And indeed ran with reduced power.
I'd really like to find the smoking gun.

 

Checked g106 and 104 which are essentially the same. Both fine. I cleaned them last summer.
Removed the inner fender cover to just have a look at the PCM and TAC module. As I suspected, white fuzz corrosion on the PCM. Esp on the bottom by the connectors. The car was purchased in NJ and driven in the winter.
I chose not to remove the PCM and TAC at this time.
It rained this am and the wiring in there was wet. The udder is not plugged. So clearly there is another way water gets down there.

I have more grounds to look at.

I wonder what the engineers were thinking when they put the brains of the car behind a panel in the wheel well?

 

In continuing to mess with this, I discovered a dead MSD plug wire. These were new last summer. I had some spares.

Just when I thought everything was happy, busted a rocker arm! I waited too long to install the new YT's. It's a long story......

Car runs excellent. Has not thrown a single code in 2 weeks.
Even the door locks work better.

Knock on wood!

 

Well crap. REP again today right when starting the car. This time just 2 codes. P1120 and a TCS code.

There is something amiss in the TPS circuit. I'll be testing all that tomorrow. This has the LS2 TB with the Casper's adapter harness.

 

Open/unplug the 6-pin flat connector on that adapter and inspect inside for moisture/corrosion, dirt, etc. Even though the connector body is designed for 6-pins, only 4 are actually used, and Casper's doesn't put filler-plugs on the other two unused holes, allowing contamination directly inside.

I trashed a Casper's harness I once had for this very reason, and bought the Racetronix adapter harness. Racetronix does it right, plus it was a couple dollars cheaper too. No more Casper's for me.

 

Thanks, I'll check that out. I had the intake off, all this stuff started right after that.
I'm always suspicious of the last thing I touched! Ha!

Edit. Well, Casper's must have changed the design. The unused pin holes were plugged.
Under the microscope, there isn't a hint of corrosion.

So on to the TAC and PCM connectors.

The final item will be the throttle body itself. The TPS is not replaceable....it's built inside the unit.

Ron