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DTC 1656

Brooklyn Tow said:
Is your solenoid plugged in?....even though you don't use it?.....(WAG) Maybe you have a bad wastegate solenoid thats telling the PCM and there is your code.

This is if your WG solenoid is still plugged in.....If the Heath programing took it out of the "loop," then my (WAG) is N/A.
Click to expand...

It is plugged in, but the vac hose on the other side is not as it would be pointless to do so without the vac pump. I've tried disconnecting the plug and running it that way and it still throws the code.

Not sure that Heath programmed it out. He indicated that he was going to adjust parameters to the ATT. The replacement ECM says MaxEtorq, whereas the one I sent him said GL4 on it.
 
Big T said:
It is plugged in, but the vac hose on the other side is not as it would be pointless to do so without the vac pump. I've tried disconnecting the plug and running it that way and it still throws the code.

Not sure that Heath programmed it out. He indicated that he was going to adjust parameters to the ATT. The replacement ECM says MaxEtorq, whereas the one I sent him said GL4 on it.
Click to expand...

Replace the WG solenoid.....If that doesn't fix it, you know it's in the programing.......
 
buddy said:
No problem.

With the truck off, and prefereably two people perhaps...

(1) place the ohm meter leads on each of the boost solenoid hareness pins (the cable end). Record ohm reading across the two pins. Shake the cable and the group of engine harness connectors behind the fuel filter manager and see if the resistance readings change and record.

(2) place one meter lead on one boost solenoid harness pin and one meter lead on the engine ground, record reading. Then shake the cable and the group of engine harness connectors behind the fuel filter manager and see if the resistance readings change and record.

(3) place one meter lead on the other boost solenoid harness pin and one meter lead on the engine ground, record reading. Then shake the cable and the group of engine harness connectors behind the fuel filter manager and see if the resistance readings change and record.

Its kind of annoying working on a circuit you dont even use. You could ask heath to disable all boost solenoid trouble codes and then cut the wires or pull the pins from the PCM harnesses.
Click to expand...

OK performed this test two ways: 1) No key in the ignition, and 2) Key in and ignition in run position, engine off.

Results:

1) Right hand pin to the plug to ground registers 11.2; the rest registered OL.

2) Across the pins registered 15+; the rest registered OL.

Shaking the wire harness does nothing, but I'll not that I only have about 4" to 6" from the plug to the main wire harness. The main wire harness is held firmly down with zip ties and brackets, thus I can only wiggle the short 4" to 6" from the main harness to the solenoid plug. I have no idea what ohm meter readings mean.

The vac tube is connected to the other side of the solenoid, but the other end of the vac tube is hanging free without any vac pump to attach to. The wastegate solenoid plug has been plugged in for the recent running, but prior tests showed that unplugging it makes no difference.
 
ak diesel driver said:
another wag here how about swapping the map and boost sensors off the 95
Click to expand...

WAG = Wild Ass Guess?

Not going to touch the sensors on the '95. Not going to mess with a truck that's now my son's and running fine to play games with the '99 that's running fine, but throwing a nonsensical DTC code.
 
I suspect it's an oddball to the program, you'll have to hook up with Bill after the holidays took me forever to clear my 1656 code, though mine did not set the check engine lite always, it would set on occasion but mostly it was in the stored incidental codes and you had to use the scan tool to see that it had been set. it's not related to the ATT install, (or at least mine wasn't) as I had that code even when I had the GM turbo on it.
 
ak diesel driver said:
another wag here how about swapping the map and boost sensors off the 95
Click to expand...

Damn, another chicken dinner winner. I swapped the MAP off the '95 and voila, the SES light goes away.

So I guess I need a new MAP sensor. RA has five choices: 1) Airtex Wells $29.79; 2) Standard Motor Products $30.79; 3) Airtex Wells $46.79; 4) Original Engine Management $56.79; and ) Delphi $56.79.

So which one do I buy?
 
Go cheap, Unless there is a significant difference in the OEM....Although some/many electrical components, OEM quality is usually what makes all the difference.
 
Is Delphi the OEM? How do I know if there's a big difference. Looks like a pretty simple part.
 
Brooklyn Tow said:
Ya lost me...
Click to expand...

Sorry, I was responding there to AK's post: "I'll take a gift certificate chicken wouldn't be any good by the time the PO got it here ."

I've driven the Alaska Hwy, even the Dalton Hwy out onto the North Slope. Would love to do it again. If I do, I'd be certain to stop by to see AK. I got a taste of his weather on Thursday in Jefferson City, MO:

IMG_0355.jpg


Next assignment is in Colorado, Boulder area. May take advantage and do some skiing. Been 10 years since I've been skiing. Still have the old slalom boards. Everyone says to use the newer parabolic skis as they're easier, but why should I when I was already at a pretty advanced level with the John Stockton length boards? Had to throw out the Lange Tii Team Heats as my feet flattened out another size. I'll be out of shape, reaction speed no where near what it was, but I'll get the rhythm back.
 
I looked closely at the photos of each MAP offering at RA and the Delphi was the right match. I'm sure the others work, but for $25 more, I just did not want to mess around.

Update: ran the truck this AM and the SES light came on again. However, played around with the code scanner as I had previously noted that I was getting two codes on the scanner: "1656" and "P 1656 P". Not that up to speed on the scanner and thought I was erasing all the codes. Apparently not, as I noted last night that the erase function would eliminate the "1656", but the "P 1656 P" was still there. I scrolled through the menu and found a "Rescan" option which had an additional "Erase" option. I'm thinking this option erases the history whereas the first erase option addresses the current codes. I try the Rescan Erase option and bingo, "No Codes" shows up. First time I've seen that in awhile. So I drive it around further and no codes appear. I shut HER down and still no codes and no SES light on at all while the WTS light is cycling. SES light never appears and no codes. I'm feeling a bit relieved as I thought that I might have made an unnecessary part order. Will do some more driving around on errands today to make sure this is the real fix.
 
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Big T said:
Sorry, I was responding there to AK's post: "I'll take a gift certificate chicken wouldn't be any good by the time the PO got it here ."

I've driven the Alaska Hwy, even the Dalton Hwy out onto the North Slope. Would love to do it again. If I do, I'd be certain to stop by to see AK. I got a taste of his weather on Thursday in Jefferson City, MO:

http://i293.photobucket.com/albums/mm50/BigThres/Mobile%20Uploads/IMG_0355.jpg[/IMG

Next assignment is in Colorado, Boulder area. May take advantage and do some skiing. Been 10 years since I've been skiing. Still have the old slalom boards. Everyone says to use the newer parabolic skis as they're easier, but why should I when I was already at a pretty advanced level with the John Stockton length boards? Had to throw out the Lange Tii Team Heats as my feet flattened out another size. I'll be out of shape, reaction speed no where near what it was, but I'll get the rhythm back.[/QUOTE]

-30 here this am
Click to expand...
 
Another update: Colbythekid got his new 170 amp alternator. So I went out to show him my status with the codes AND the SES light comes back on when I go to start it. Both the P 1656 and P 1656 P. I do the clear again and shut it down showing no codes. Wait a minute, then do the start cycle again and the SES light re-appears and P 1656 and P 1656 P show up again. Now I'm really perplexed as how could I shut it down with no codes showing and then they re-appear before I even start the engine?
 
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