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DTC 1656
- Thread starter Big T
- Start date
Big T
Well-Known Member
No I haven't. Spoke to Bill Heath specifically about doing this (i.e. replacing the wastegate solenoid) and he said it would do nothing. No vacuum hooked up to operate it = nothing. We then focused on the MAP.
Went out to check it again and again the 1656 code appears. Once again I got it to erase and show "No Codes" then shut it down. Left the ignition off for a couple minutes with the code reader pulled. The plugged in the code reader and turned the ignition on and the the P 1656 P appears again, but no SES light. I bet the SES light reappears after a sustained run.
Well, Colbythekid took off, which means I can go pull his boost sensor and try it on mine. Actually, he gave me free rein for the whole weekend to play with this.
Big T
Well-Known Member
Nuther update: Again got it to No Codes. Turn ignition on with No Codes showing and no SES light, then scroll down to Rescan and it shows 1 code pending and it's the P 1656 P.
Tried/borrowed the boost sensor from Colbythekid's and no change. Still the same result. Restored Colbythekids as I'm out of options. Time to talk to Bill Heath again as it really seems to be circling back to the program.
One thing to point out: the plug to the MAP is falling apart. It was already broken and held firmly in place by a zip tie. More broke off while doing this work. One female tube broke out. I'm sure it's connecting properly, but wondering if I might benefit from splicing a new plug on? If so, then where do I get such a plug?
Broken plug on left:
Plug zip tied to the MAP:
Tried/borrowed the boost sensor from Colbythekid's and no change. Still the same result. Restored Colbythekids as I'm out of options. Time to talk to Bill Heath again as it really seems to be circling back to the program.
One thing to point out: the plug to the MAP is falling apart. It was already broken and held firmly in place by a zip tie. More broke off while doing this work. One female tube broke out. I'm sure it's connecting properly, but wondering if I might benefit from splicing a new plug on? If so, then where do I get such a plug?
Broken plug on left:
Plug zip tied to the MAP:
buddy
Active Member
Mine is the same way, but I bought a new plug with pigtail from Rock Auto to go on sometime.
Big T
Well-Known Member
Part # or link please.:agreed:
Mine is the same way! Good ole zip tie! I don't know if it would matter I was told that having the wastegate solenoid still hooked up keeps the ecm in check? Could you try to put the 95 WGS on it or are they different? Seems like it would be an easy thing to try. GM part number on the boost sensor is 12569241 If you get one make sure they give exact match.... been there and done that one!
Big T
Well-Known Member
Yes I can swap the wastegate solenoid from the '95. That old '95 is begginning to feel like a Chinese prisoner being harvested for parts.:hihi:
ak diesel driver
6.5 driver
looks like I have to give back my coupon. Sigh oh well if I must
buddy
Active Member
http://www.rockauto.com/catalog/raframecatalog.php?carcode=1144033&parttype=2597
I got {#12085502}, but there is an ACDelco option.
Costly little connector.
buddy
Active Member
I missed this post, I will see how it compares to my truck tomorrow.
Big T
Well-Known Member
Update: Borrowed the solenoid from the '95 AND same result.
This time I used the iPhone to take a sequence of pictures of the Code Reader to show what's happening:
After driving it, shutting down then restarting and the SES light stays on, the next to last photo would show Fault: 01, Pend: 02. The last photo would show P1656, 01/02, then P1656 P, 02/02.
The photos show me unplugging it, then plugging it back in and the code reappearing, this after the scanner said there were no codes prior to unplugging it. So you can see, I am at a complete loss on this.
This time I used the iPhone to take a sequence of pictures of the Code Reader to show what's happening:
After driving it, shutting down then restarting and the SES light stays on, the next to last photo would show Fault: 01, Pend: 02. The last photo would show P1656, 01/02, then P1656 P, 02/02.
The photos show me unplugging it, then plugging it back in and the code reappearing, this after the scanner said there were no codes prior to unplugging it. So you can see, I am at a complete loss on this.
Last edited:
Brooklyn Tow
9 11 Never Forget
Maybe its a history code, or "soft code" like tim said.......Try hooking up to a better bidirectional scanner/reader, maybe there is something your missing.
BTW, I have the Newer model of that pocket scan......if thats a Actron, all they do is read and clear, but better than nothing.
BTW, I have the Newer model of that pocket scan......if thats a Actron, all they do is read and clear, but better than nothing.
buddy
Active Member
Its setting his SES light though.
Now it seems like you have a ecm/pcm problem. There is no way that it could give the same on a different WGS. The ecm/pcm seems to keep setting the code unless you have a bad wire some where. Have you tried a full battery kill to erase memory to rule out your code reader screwing up?
Big T
Well-Known Member
Yeah I posted the pic sequence in the hopes that I'd get some comments. I was wondering if it was a history code that was not clearing. That reader was $40 with shipping off eBay. I know I need to get a better one, like a Car Code, but this one has more than paid for itself.
Big T
Well-Known Member
Have not tried the full battery kill to erase memory, but that can be done. Do I just need to pull the grounds for 20 minutes? Come to think of it, the ecm was just reprogrammed and installed, yet it's setting the same code as before. So it really can't be some historic code in the memory.
NVW
Well-Known Member
Yes, just the grounds. 5 min. is enough
buddy
Active Member
I would ask Bill Heath if they sent you a different PCM or just reprogrammed the one you sent them. Could have been that the one they sent to the PO with the GL4 program was a PCM with a intermittent hardware issue.
Big T
Well-Known Member
Buddy, this ground was already covered with Bill. It's a different PCM with updated programming for the ATT. The prior PCM had a label with the PO's name on it; this one does not. Bill pulled up the specific programming for this PCM while I was on the phone with him. I will note that the prior PCM was doing the same thing: throwing the 1656 code.
I will do another round with Bill on the phone, but I've about given up on solving this and I am warming up to just living with the SES light. Had been using the code reader to turn it off, but it's already getting old and I'm getting used to the SES light being on all the time.:nonod:
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Brooklyn Tow
9 11 Never Forget
WAG= could the PCM be WG programed instead of TM programed= WAG
Or just have a BAD WG solenoid plugged in.....and it's making the PCM angry?