FUN with computers - '96 Passat OBD-D vs OBD2 I think mine is OBD-D, now what???

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
I bought an Ultra-Guage so I could get some real-time fuel economy feedback... (It's an aftermarket mini scanner that plugs into the OBD port.) It just arrived, and it doesn't work on my car because I have the "other" ECU protocol; I think its caled "OBD-D?" I looked and my ECU has a black plastic housing, and the plug in my dash is purple. To be totally honest, I don't really know much about the differences, and I would love some help being pointed to where I can read and learn a bit more.
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So first, where can I read more to better understand and appreciate this system, and its strengths & weaknesses comapred to the more standardized OBD2?
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Second, is there anything I can do to make this little gizmo work? Some of you use the "Scanguage" brand... would that work on mine? I just really, really, really am obsessed with trying to get better MPGs in this car, and it seems being able to monitor this data in real time would significantly help. I would love any suggestions regarding this as well...
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in this vein, I drove the car about 400 miles the other day on a little Texas Hill Country road trip and got about 45mpg. AC was running max the whole time, it was very hilly, and the roads where a bit stop and go, but I was hoping for better fuel economy.. My two around town top-ups have all been about 35mpg, and that is with me driving aggressively, with long periods of idling with the AC running as I do interior work in the car while its about 105°F out there... Texas heat is brutal.
 
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vwxyzero

Veteran Member
Joined
Jul 12, 2004
Location
Los Angeles, CA
TDI
'96 Passat Sedan, '96 TDI Passat Wagon, & Jetta Sedan, '83 Turbodiesel (IDI)
45 MPG is pretty good for that car in the heat and terrain you describe.

Still OBDII. Can't remember if it's the "black box" or silver boxed ECU that's the updated version, but somebody else will know, I'd look, but my TDIs are on the other side of town from me.

BTW, idling for long periods of time has its detractors as well as its advocates. My personal opinion is that's a bad practice.

You really need to find somebody in Austin Texas that has VCDS VAG-COM - start here: read the fist half dozen posts and then search for a listed club member near you, it's an invaluable resource I've used over the years.
Check it out here: VCDS VAG-COM. Try this link: https://forums.tdiclub.com/showthread.php?t=296841

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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4, '97 Jetta
Your around town mileage pretty much matches what I see with my 3 TDIs. I don’t do a lot of highway, so I’ve just learned to accept it.

If you have the black plastic ECU, you want to go to the metal GQ box. Abacus states you can use any metal box, but you need to be running the GQ chips. I’ve never needed to test his statement, since my car came with the GQ box. I believe the swap was done as part of the smoke recall on these cars.

Be aware that I’ve seen some ECUs where the chips were soldered in. They can be made to work, but it’s easier to get the correct style.

-Todd
 

vwxyzero

Veteran Member
Joined
Jul 12, 2004
Location
Los Angeles, CA
TDI
'96 Passat Sedan, '96 TDI Passat Wagon, & Jetta Sedan, '83 Turbodiesel (IDI)
Your around town mileage pretty much matches what I see with my 3 TDIs. I don’t do a lot of highway, so I’ve just learned to accept it.

If you have the black plastic ECU, you want to go to the metal GQ box. Abacus states you can use any metal box, but you need to be running the GQ chips. I’ve never needed to test his statement, since my car came with the GQ box. I believe the swap was done as part of the smoke recall on these cars.

Be aware that I’ve seen some ECUs where the chips were soldered in. They can be made to work, but it’s easier to get the correct style.

-Todd
Agree. And yes it was part of the smoke recall and useless 5th injector ahead of the catalytic converter. I'd be surprised if it's the original ECU and still has the 5th injector active, but stranger things have happened.


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Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
The black box is the BK ECU and it is OBD-D. Very little will recognize it and the Ultra/Scangauge will not. I have a few on the shelf from swaps. If you have it then odds are good you still have the 5th injector hooked up. The good thing about this ECU is that it will self-clear trouble codes when they go away, the others will 'latch' them until they're cleared manually. It was a dual board ECU that could be tuned but not easily.




Here is one with the silver case:




I have used the FA/GQ/ED/and JB ECU's in my B4 with the proper chips (FA for '97 and GQ for '96) without issue numerous times. Many people I know are also running them. They are all OBD-II and can be read by most code readers and aftermarket setups. My brother even used a wireless in his and transmitted the real time data to his phone.

The BK ECU was used in the 1996 B4 TDI and was stock. Its replacement was the GQ for 1996.

The FA ECU was used in the 1997 B4 TDI.

The ED was used in the 1997 A3 TDI, but some were problem prone.
The JB was used in the later 1997/1998/ and 1/2 year 1999 A3 TDI's.

Some had soldered on chips but every one I have seen has swappable chips in it.

 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
This is all great information. If I want to shop for one on eBay, or buy one from a forum member, how do I tell if an ECU is a "GQ" unit?
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
It'll say right on the outside case.
I am looking at ECUs on eBay, and not seeing the markings that you described.
EDIT: okay... I see its on the parts number, the last two numbers are "GQ" -- 028 906 021 GQ
Abacus... after re-reading it about 10 times, I am finally understanding. Your info was clear, it just took me a bit to understand.
FA/GQ/ED/and JB are compatable "base ECUs, and if I had a GQ chip set, I could swap them into these units... Got it.

Do you know if all the "028 906 021" ECUs compatable with the GQ chip set?

Also, I believe the 5th injector is disconnected. There is a diesel line with a fancy connector that is disconnected, and tucked behind my airbox. I am not 100 certain, but I am guessing its this thing.

Thank you!
 
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vwxyzero

Veteran Member
Joined
Jul 12, 2004
Location
Los Angeles, CA
TDI
'96 Passat Sedan, '96 TDI Passat Wagon, & Jetta Sedan, '83 Turbodiesel (IDI)
Also, I believe the 5th injector is disconnected. There is a diesel line with a fancy connector that is disconnected, and tucked behind my airbox. I am not 100 certain, but I am guessing its this thing.
Probably, but there's more than just disconnecting the fuel line, it also had to trick the Computer. Do a deep search for 5th injector delete on this forum, it goes way back.
Also your very first post says you bought it from a forum member, call him/her to see if the delete was done and wheather the black ECU box has the later chip set and board. No reason to fix what's not broken. Research it.

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Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
Those are the only ECU’s of which I’m aware that are compatible. To have a BK ECU tuned is very rare as most tuners didn't waste their time due to the availability of the newer ones.

The 5th injector is disabled with the newer ECU. Odds are very good you could find some stock GQ chips from people who installed tunes on theirs. I may even have a set but I’d have to look. I’ve swapped a ton of ECU’s for people over the years and some got tuned chips.
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
I found some $20 GQ chips on eBay and went ahead and snatched them up. I still want a "silver" ECU to make my B4V OBD2 compliant for the simplicity of future easier diagnostics...

Does anyone have an ECU housing they want to sell cheap?
 

turbodieseldyke

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Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
98 jetta
I tried buying two cheap ecu's off ebay, figuring the silver-box foreign versions would have swappable chips. They didn't.

If your GQ venture doesn't pan out, there's also the MFA option, if you can find the cluster and wiper stalk. See Chris Bell's sticky thread for details.
 

quartersaw

Veteran Member
Joined
Sep 20, 2005
Location
Albany, NY
TDI
2002 Jetta Wagon, '96 B4V,'99 2 door Golf
I tried buying two cheap ecu's off ebay, figuring the silver-box foreign versions would have swappable chips. They didn't.

If your GQ venture doesn't pan out, there's also the MFA option, if you can find the cluster and wiper stalk. See Chris Bell's sticky thread for details.
I took my (long gone)'97 in for the recall, so I could have a new intake manifold installed. They swapped the ECU out with a soldered chip version.. :-(
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4, '97 Jetta
You went in for an intake and they swapped the ecu? Was that part of the recall?

-Todd
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Glad you found the GQ chips, would not suggest trying to run the ED chips, that ECU can be flaky and was only used short time on 97 Mk3 tdi cars.

I've never experienced a problem with mine but have read where others have. Preferred ECU for Mk3 is the JB ECU, the last of the series.

I've compared the engine wiring (ECU) for the Mk3 vs a 96 B4 tdi cars and found little if any difference. Primarily the connections for the 5th injector and the catalyst sensors, which were later removed via the recall.

I honestly think that a person with the OBD2 setup could run any of those ECU's and be fine. Whether that translates to the OBDD wiring I can't say though, but it might, and since VW was doing ECU replacements as a function of the recall I have to believe the wiring is the same.

Steve
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
Glad you found the GQ chips, would not suggest trying to run the ED chips, that ECU can be flaky and was only used short time on 97 Mk3 tdi cars.

I've never experienced a problem with mine but have read where others have. Preferred ECU for Mk3 is the JB ECU, the last of the series.

I've compared the engine wiring (ECU) for the Mk3 vs a 96 B4 tdi cars and found little if any difference. Primarily the connections for the 5th injector and the catalyst sensors, which were later removed via the recall.

I honestly think that a person with the OBD2 setup could run any of those ECU's and be fine. Whether that translates to the OBDD wiring I can't say though, but it might, and since VW was doing ECU replacements as a function of the recall I have to believe the wiring is the same.

Steve
Thanks Steve. I received my GQ chips a few days ago, and I found a reasonably cheap ($80) ED computer on evilBay, and it is going to arrive tomorrow or the next day. I am hoping to see what it does this weekend.
 

Phi1osopher

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Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
Since I had a "black" OBD-D ECU in my '96 B4V passat wagon, I went ahead and bought a "GQ" chip set and a cheap "ED" ECU from evilBay (028-906-021-ED). I chose the ED simply because it was the cheapest one there.. The chips were removable and I swapped in the GQ chips. I was a bit nervous, but it really was very easy.
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I was surprised when I went on my test drive that my Passat was immediately and significantly more peppy. There definitely is a bit more zip. I also discovered that I apparently had a code, P1144 waiting for me (Mass Air Flow Sensor Open/Short To Ground).. but I'll sort it out soon enough. It looks like my check engine warning light's LED conveniently does not illuminate...
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The thing that inspired this effort was I wanted my aftermarket "UltraGauge" computer (it plugs into the OBD-2 port) to help me monitor fuel efficiency, but it would not interface with my OBD-D ECU. Happily it seems to work just fine with my new OBD-2 ECU. I also wanted to be able to easily check and clear codes, since very few people have equipment that can interface with the unique OBD-D protocols.
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The inside of my 'new' ECU

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Replace the hose with a silicone one

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These are the ED chips.

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Now that I have a spare (ED) chipset, as well as my untouched black ECU, I hope to explore if I can take the ED chips and install modified GQ performance on to them + install different injectors, and maybe a few other simple performance upgrades. I also am curious if there is some easy way to find out if the GQ chips I just bought and installed are stock or if they are modified. The car certainly is a bit quicker, and I think I saw a small puff of smoke in the headlights of the person behind me when I floored it this evening -- something I've never previously observed. I do have a "VAG-COM" usb cable, so I might just download the program and start trying to explore all that stuffs.
 
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Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
The ED chips are probably not writeable. You can get the chips, software, and hardware to make your own, but unless you know what you're doing, I highly recommend against it. It is too easy to mess up the car permanently.

If the GQ chips are tuned, then look to the Mass Air Flow Sensor readings, it will most likely show the 'specified' as a fixed value, like this on my B4 sedan with the RocketChips



And this is on my B4V with the Malone tune:




The Vag-Com is a VERY powerful tool for diagnosing issues and fine tuning how the car runs. It is simply amazing once you learn how it works and can interpret the data.
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
The ED chips are probably not writeable. You can get the chips, software, and hardware to make your own, but unless you know what you're doing, I highly recommend against it. It is too easy to mess up the car permanently.

If the GQ chips are tuned, then look to the Mass Air Flow Sensor readings, it will most likely show the 'specified' as a fixed value, like this on my B4 sedan with the RocketChips

The Vag-Com is a VERY powerful tool for diagnosing issues and fine tuning how the car runs. It is simply amazing once you learn how it works and can interpret the data.
Thank you, Abacus! I am a fairly experienced and knowledgeable mechanic, but I don't have any experience with Vag-Com (am I the only one who giggles at the name?) nor do I have any experience with tuning/programming chips. I am generally pretty good at learning things, and taking some chances for more complicated and challenging DIY projects.

Is it your experience that you need a set of "programmable chips" to program them? I've read a bit about folks downloading, or purchasing "tunes" which are emailed to the end user. I was unsure if the car owner who was installing these was installing them onto an aftermarket or stock chipset.. I thought that since I have two chipsets, and I can't use the ED ones, if they are re-writable, I would experiment with those while keeping the GQ chips stock. Or do we need special hardware to re-write the chips... I guessed/ imagined that this was doable with them mounted in the car, and the stock ECU had this capacity..
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
Oh, and regarding the P1144 code - I have not dug into this at all, but the car is 100% asymptomatic. It runs perfectly. I am almost certain that at one point I had the air mass sensor unplugged with the car running at some point, and that must have triggered this code, then stored it. I'll try to clear it out later; It's highly unlikely to be a real code for me.
=)
 
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