I started another thread about this earlier in the summer, but it was a bit convoluted, so I didn't get much in the way of a response. I wrote this summary for a local friend, and I'm talking to DP-Tuner about this, but I'd love your thoughts and insight. What could be wrong?

Current Symptoms

SES light when turning key to "on". It happens randomly every few days (vehicle driven 1-2 times per day). It never goes out while driving, but nearly always fails to reappear after a key cycle, or two, or three. Vehicle runs fine in all tunes. AE will almost always show P1000, P0603, and P0541. (I know the last two are benign, but most folks seem to see P1000 rarely, and I'll see it most every time I check, no matter how long it's been since the batteries were disconnected.) Occasionally it'll show another code, seemingly somewhat randomly. They include:

P1397 - Only once, just the other day
P1832 - Maybe three times in the last few months
P0107 - A couple of times in the last few months
P0500 - Only once

The goofy thing is, I can drive it for minutes or hours with no light. Turn the key on later - minutes, hours, doesn't matter - and not have an SES. Turn the key on later - again, minutes or hours - and the SES will light immediately. Literally, nothing would have changed from the time before, but the light comes on. (shrug)

Troubleshooting Steps

From most recent to earliest...

Replaced alternator (8/21/11) - This was a replacement for the one I put on in April, on the chance that it was the original source of the problem. As noted below, the old alternator tested good several times, but the parts store agreed to warranty it.

Replaced alternator pigtail (8/19/11) - This was a just-in-case thing, since the alternator itself tested good.

Grounded PCM (8/12/11) - I noticed the other night that the grounding clip was missing, and I assume it has been for a long time. I grounded the PCM by duct taping (for now) a copper ground strap to the exposed PCM case, and connected the strap to the PCM mount bolt where the clip usually goes. I'd have bet this fixed the issue, but I've had several SES lights since then.

Reseated PCM and F5 (8/12/11) - Both appeared to already be securely fastened, but I reseated them, anyway. James showed Jody some pics I took of the PCM connector, and Jody thought there was a little more copper showing than he'd like to see. The F5 seems to attach securely, though.

Removed F5 (7/30/11 and again on 8/23/11.) - I didn't have any SES lights with the chip out but, in hindsight I'm wondering if I left it out long enough. I can sometimes go several days without a light. EDIT: No issues in ten days after 8/23, so I'm now confident the problem only occurs with the F5 installed.)

Disconnected Batteries (Late july, 11) - Thinking this would "reboot" the PCM (Hey, it works on Windows, right?). All was well for a few days/drives, then the problem returned.J

What's Changed on the Vehicle

5/11 - SES light came on while driving. I had Pocket read the codes for me, but I think all he mentioned was the P1000. This is the *only* time the SES has come on while driving. I still remember it happened just as I hit the CC Resume button, towing in 80T.

4/11 - Replaced a failed Autolite alternator with an Ultima one. (Both cheap ones from O'Reilly.) When all the SES stuff started I had the Ultima alternator tested. It passed, for what that's worth.

2/11 - Replaced a failed CPS with a black one.

9/10 - Installed F5. Still no unexplained SES'. (I left the air filter sensor unplugged once, and that triggered one.)

Before 9/10 - Never an SES in eight years.

5/03 - Bought vehicle with 60K on it. The PO had a Hypertech III installed, and I'm *almost* certain he removed the program before selling it. The Lie-o-meter has been remarkably accurate over the years, so I'm assuming the PCM programming is stock EBM2.

Everything else I've done to the truck in this time has been mechanical - bellowed pipes, etc.

I'd really appreciate any insight or suggestions. I've got a live tuning date in early September, and would love to have a few SES-free weeks before that date.

Thanks,

Mark

 

Boost fooler, Ive gt the same thing going on right now I just have to adjust my fooler

 

The light comes on with the engine off. Doesn't the SES set for overboost immediately when the threshold is exceeded?

Mark

 

Does the light go off once the engine is started?

 

No, but it does after one to several key cycles.

 

Edit: The overboost code is P0238, which I've never seen.

Isn't there a specific code for overboost?

 

I'd start by removing the DP for a few days and see if the problem goes away. It sounds like it may be nothing more than some quirk in the computer. I've seen my glow plug light act that way a few times over the years. My light will go a year or two between acting up, but I think it has something to do with the way the PCM powers up.

I've seen a bad chip (not saying yours is bad) cause an intermittent no start and had it explained to me something about the check sum on start up not something or other blah, blah, blah. It was over my head, but it had to do with the way the chip and PCM powered up when the key was turned on.

 

I came to the same conclusion while proofreading my original post. It's out now, with one test drive completed. I'll run it this way at least a week.

Mark

 

I took the F5 out the other night, and now have 200 miles on it since then, including a tow through the rockies today, and lots of starts and key cycles.

No SES light. No issues, at all. (Other than not enough power...) Also, the PCM passed the AE KOEO test, which it always does without the chip.

What does that tell me?

Mark

 

Check the connections on the chip / pcm for any corrosion or issues. Sounds like there's an issue with the chip during the power up cycle. If I were in your shoes, I'd just call Jody and ask for advice, or shoot an email to Diane.

 

Here's how the connection looks





It looks OK to me, though I don't remember quite that much copper showing when I originally installed the chip last September. I thought about having the connection re-tinned, but I can't find a place that'll do it, and I'm not that good with a soldering iron.

I've been working with DP but, until now, we didn't have definitive evidence that the problem only occured with the chip installed.

Mark

 

Keep DP updated on what you've found. You should be able to find one of your local club members to re-tin the contacts for you if it comes to that, but I'd make sure it's not a circuit issue first.

 

Well, I'm 10 days into my "no F5" test, and have seen no issues. I'm now certain the problem does not occur with the chip removed, and does occur with it installed. But, what's the cause? Connection? Chip issue? Programming issue/incompatibility? Something else?

Hoping to talk to Jody in the morning.

Mark

 

Just talked to Jody. (Good guy. I'd not actually spoken with him before.) We don't yet know what's wrong, but at least have a plan to figure it out.

Mark

 

I wanted to close the loop on this issue. Strictly speaking, the problem turned out to be a contaminated connection between the PCM and F5. The night of my last post I was looking at the photos posted above, and saw a few specks that I'd never noticed with my naked (and 53 year old...) eye. When I went to reinstall the chip, I looked closely, and could see a few. I cleaned the PCM and F5 connection surfaces, and ran it 500 miles over the next week with no SES light.

The real root cause, though, was that I took too much of the tin off the connector, and that either allowed, or was the source of, the contamination. In my live tuning session Saturday, Jody's emulator wouldn't even stay connected. He re-tinned the PCM connector (in something under 5 minutes - it was impressive) and that made for a much tighter connection, both for the emulator, and my chip.

Life is good.

Mark