Savage42

Hey guys! After a decade of work, I'm working on the final details of finishing my LS6/4L60E conversion into my 1978 Datsun 280Z. I'm hoping you guys can help out with these issues.

Here's the rundown on what I've got for a setup:

2002 Camaro LS6 / 4L60E with factory PCM and harness made into a standalone. I have a CAI, headers, ported TB (stock with cable throttle linkage). I had the PCM flashed many years ago to get rid of the VATS, secondary O2 sensors, etc. I know that I will need to get the car tuned on a chassis dyno by a quality tuner to really get it dialed in, but I did get the car started and running pretty well, at least for a half dozen times I started it, let it run for a little while to get some heat in it and shut if off.

This last time, I'm getting the "Reduced Engine Power" and "Service Engine Soon" message on the bottom of the 2002 C6 Z06 instrument cluster I have wired up and will be integrating into the dash. After doing some reading, I'm assuming that the fact that I switched to the Z06 MAF from the stock Camaro MAF (85mm vs. 75mm) may cause this fault since the MAF tables need to be adjusted? I told the guy who did the original flash this, but this was a decade or so ago, so knowledge about tuning these things have come a long way since then and I'm not sure that he did that.

I had a friend come over and hook up his OBD2 scanner to my car and kept getting a Communication Link error, so it wasn't getting a signal. I got the OBD2 connector pre-wired and I ran the green data wire (same one running the instrument cluster), so it should work. When I looked up a wiring diagram online for the OBD2 port, it was wired the same way (in regards to pin out), but it shows the data wire as purple instead of green. I also have the OBD2 port that I cut out of a 2002 Corvette and it has booth a green wire (in the 14 slot) and the others like the diagram. Can someone tell me why the Corvette connector is wired differently? See below.

Need to figure out why I can't get communication established in order to see what codes are being triggered. Anyone have any ideas? Thanks in advance.

truckdoug

iTrader: (25)

green or purple, as long as the data wire goes to pin 2 on the obd plug and pin blue 58 at the pcm it should be fine.

you got it key on engine off right? is the +12v to pin 16 on the obd plug hot when keyed?

Lsxford

iTrader: (6)

Make sure the 2 grounds are good also. I use a taillamp bulb and socket, both elements of a 3157 bulb, and it has some small leads attached. Stick it in the power and ground terminals at the port and make sure it burns good and bright. Can also do a volt drop test if you wanna be real technical.

Savage42

I took the meter to the orange wire (constant power, not switched) and all good there. I will check the ground, but it is attached to the same place the grounds for the instrument cluster are attached and that works fine. Very strange, but worth a try.

Lsxford

iTrader: (6)

If the port has good power and grounds and the comm wire is good id look for a different scan tool. What tool was your friend using? Just a small cheap code reader?

Lsxford

iTrader: (6)

Also theres 2 grounds, 4 and 5. Some scan tools dont need both but some do

Savage42

Harbor Freight reader. http://www.harborfreight.com/can-obd...abs-60794.html

Not high dollar, but works fine on his C6 Z06 and his SuperLite with LS7 power.

It could be the issue. I'm looking to get a bluetooth OBD2 adapter and the app for my iPhone.

truckdoug

iTrader: (25)

did you tone the data wire to pin 58 on the blue pcm connector?

Savage42

Yes, same wire that runs all of the gauges, message screen, etc. and those all work.

truckdoug

iTrader: (25)

did you actually verify continuity with a VOM between the obd pin 2 and pcm pin C1 58?

Lsxford

iTrader: (6)

I thought pcm communicated with other modules over the other com wire? The 1 not needed for standalone, this is a different animal than im used to tho lol

Im with doug! Maybe even overlay a new wire from pcm to obd2 port, bypass the ic just to see if pcm will communicate

pdsq98gt

Make sure the battery is good and charged. I've had a couple of vehicles that started great but I couldn't get a scan tool to communicate. Hooked a battery charger to it and it worked. Btw both had a red top optima in it. Coincidence? Also c5 vettes were kind of picky about just having the PCM and the scan tool in the communication loop. The other modules (IPC) could be interrupting the communication.

Savage42

i have the data wire splitting off into 2 wires at the middle of the dash (PCM on passenger side) with a couple feet going to the IPC and other running just slightly longer to OBD2 port, so wouldn't it be the same as running 2 wires that just going a few feet farther upstream at the PCM?

Lsxford

iTrader: (6)

So youre using the camaro pcm and corvette cluster? If so idk if they have the ability to work that way. I would unplug the cluster and see if communication with pcm is restored.

If you have cluster and pcm both from the corvette then im not sure. But as soon as our power comes back on ill look at the vette diagrams.

Lsxford

iTrader: (6)

Its strange to me that the gauges work but wont communicate with a scan tool. Id still unplug cluster and retest tho. Like i said before, this is a way completely different animal than im used to

Savage42

Correct! Both the C5 Z06 cluster and Camaro PCM are from 2002. Strange that both clusters are controlled by the PCM aside from the oil pressure gauge, which got a dedicated signal in the Camaro, where the Corvette is a serial gauge like the rest of the cluster. (somewhat annoying since that gauge doesn't work now)

I did get a bluetooth ODB2 connector and downloaded the Dash Command app on my iPhone. It connected with no issues, but this was with the cluster unplugged, so I have to go back and try it when it's "hot" to see if it was something to due with them both being hooked up or if it was possibly the scanner we used just didn't like it. That first scanner was getting some data, but was slow and timed out, so it may be a case where I have to disconnect the cluster when using the OBD2 port, but I'll figure that out later.

Also of note, the data wire is dark green at the PCM and OBD2 port, but is gray on both the Corvette & Camaro clusters. I assume the data wire goes from the PCM to a BCM and then the cluster since that would explain what controls the ABS, TC and Air Bag lights that I would like to turn off?

With the Dash Command, there were NO codes listed or saved, but under the Pre-Monitoring section, it did have warning for the O2 sensor and O2 heat. I wasn't sure if this is coming up because the secondary 02 sensors were removed (along with VATS) when I got the PCM flashed or not. I wouldn't think this would be enough to trigger the "Reduced Engine Power" situation and would assume anything dramatic enough to kick in the REP would store a hard code, but there were none.

Lsxford

iTrader: (6)

Heres the diagram, it shows them going through a star connector? Which looks like a splice pack to me. Then goes to the DLC on a purple wire to pin 2.

And this is the DLC diagram.
DLC=obd2 port

I believe the problem is corvette ic and camaro pcm, but i really dont know.

Camaro diagrams are basically the same so it should work. Id imagine the pcm isnt telling the ic what the ic is expecting to see. Maybe itll be fine when you plug the ic back up lol