General MMCD Com Error?

[skifreee911]

i just got the cable and mmcd. i have everything hooked up right i think. i can turn the injectors off and everything but when i try to check the codes it says com errror. it also wont do anything when i try to look at rpm or anythign like that. do i need the null modem adapter or whats goin on?

someone has to know the answer to this.

 

[BlackbirdOfPrey]

You are using a Serial hotsync cable and not a cradle right?

 

[BoostedTalonTS]

By chance, do you have a '90 DSM? I can't tell from your profile.

I've heard that the '90s have issues with using the MMCD for code retrieval/clearing. If this is the case, you will have to extract codes "manually" by using a multimeter between pins 1 & 12.

Otherwise, you may have a bunk cable

 

[skifreee911]

I have a 91, it wont let me see any of the RPMs, etc though.

 

[BoostedTalonTS]

The null modem adapter thing is for 2Gs... '91 huh? -Is that the build date? If so, then chances are that your cable has issues. Have you tried pulling codes from the ECU via a meter yet (just to be sure that the ECU is functioning properly)?

-If you are having "ECU COMM" Errors, then the cable is working, but if you have "Serial Comm Error" then the problem is in the cable. -What do you have?

 

[skifreee911]

i dont remember what error it gave me. it is in the shop getting a new xfer case right now. i got the cable off of ebay and the ecu just got rebuilt so im pretty sure it is fine. its a 91 model year.

 

[BoostedTalonTS]

Find out when you get it back (I hope that your new Xfer case is being replaced under the TSB/warranty/recall).

 

[skifreee911]

it is. ill let ya know when i get it back. thanx for your help.

 

[steve]

..I've heard that the '90s have issues with using the MMCD for code retrieval/clearing. -If this is the case, you will have to extract codes "manually" by using a multimeter between pins 1 & 12.

TMO's logger throws up a warning that it can't clear the error codes when it sees a '90 ECU ID but MMCd doesn't seem to have a problem reading or clearing the codes on the '90 ECUs I've seen. I check, force, and clear the codes on them all the time.
This was incorrect. The '90 ECU code doesn't have the command to clear the codes via the DLC interface. I don't know what I was thinking at the time.

The null modem adapter thing is for 2Gs...

Nope, more bad information. The null modem adaptor is part of the solution for converting from a cable setup for one style device (PC or Palm) to use it with the other.

-If you are having "ECU COMM" Errors, then the cable is working, but if you have "Serial comm error" then the problem is in the cable. -What do you have?

A "Serial Comm Error" means MMCd is seeing nothing on the RXD line and "ECU comm error" means that MMCd saw it's command echoed back but never received a response from the ECU. A bad cable can cause both errors, but you will get a "Serial Comm Error" is the cable is disconnected and a "ECU comm error" if the ECU is disconnected but have a good cable.

Steve

 

[skifreee911]

so should i get a null modem adapter and see if that fixes the problem?

 

[BoostedTalonTS]

TMO's logger throws up a warning that it can't clear the error codes when it sees a '90 ECU ID but MMCd doesn't seem to have a problem reading or clearing the codes on the '90 ECUs I've seen. I check, force, and clear the codes on them all the time.

Nope, more bad information. The null modem adaptor is part of the solution for converting from a cable setup for one style device (PC or Palm) to use it with the other.

A "Serial Comm Error" means MMCd is seeing nothing on the RXD line and "ECU comm error" means that MMCd saw it's command echoed back but never received a response from the ECU. A bad cable can cause both errors, but you will get a "Serial Comm Error" is the cable is disconnected and a "ECU comm error" if the ECU is disconnected but have a good cable.

Steve

I stand corrected (the ECU MASTER has spoken)...

The null modem adapter could be used for connecting either a palm pilot or laptop, depending on how the logging cable was made (but I usually see them used on 2Gs, with their pocket loggers)

Thanks Steve (BTW, thanks for your ECU pic I "borowed" from your ECU part number comparison post on FT... I used it to illustrate the visual differences of an EPROMed vs non-EPROMed ECU in another thread)



Back on topic:
Skifree, did you buy your ebay cable that was meant for the Palm pilot or a laptop?

 

[yugotdonkey]

I was having the same issues with my eBay datalogging cable. Turns out the cable was designed to be connected to a PC. I got the null modem adapter after searching for hours through posts, mostly by Steve (he seems to know his shit ). And the logger worked fine. Couldn't cost your more than 5 bucks at Radio Shack.

 

[steve]

(BTW, thanks for your ECU pic I "borowed" from your ECU part number comparison post on FT... I used it to illustrate the visual differences of an EPROMed vs non-EPROMed ECU in another thread)

I saw. I stole that from Todd Day off the TMO site. But I was scratching my head trying to figure out what it had to do with the thread discussion.

so should i get a null modem adapter and see if that fixes the problem?

If the sex of the connectors between your logger cable and your hotsync cable mate then you shouldn't need to, but we've seen a whole lot of brain dead people making logger cables and anything is possible.

If you do a search you'll see a couple of examples where the cables were wired backwards, with the wrong parts, and with the wires just twisted together rather than soldered. If you can post a clear picture of the DB9 connector with the covers off, so I can see how it's made I can tell you what's wrong with it.

Steve

 

[BoostedTalonTS]

I saw. I stole that from Todd Day off the TMO site. But I was scratching my head trying to figure out what it had to do with the thread discussion.

In that thread, the thread starter might be interested in my old EPROM that I used to cure my 2G MAS & 510cc injector + too much timing advance problems. I was showing him what to look for, to see if my old EPROM would even work with his ECU. Since I can't send pics via a PM, I posted it back in the original thread.

If he does have an EPROMed ECU, then he might be looking into your services in having a socket installed.

If the sex of the connectors between your logger cable and your hotsync cable mate then you shouldn't need to, but we've seen a whole lot of brain dead people making logger cables and anything is possible.

If you do a search you'll see a couple of examples where the cables were wired backwards, with the wrong parts, and with the wires just twisted together rather than soldered. If you can post a clear picture of the DB9 connector with the covers off, so I can see how it's made I can tell you what's wrong with it.

No rocket science here...
(on the DB-9 pinouts) you should have:
pin #2 1N914 diode (anode side)
pin #3 diode (cathode side), ECU comm wire (OBD1 pin#1), and 1 leg of a 10k 1/4 watt resistor
pin #5 other leg of 10k resistor, and ground/jumper wire (for OBD1 connector pin #s 10 & 12)

If the cable was made like this, then no cable null modem adapter is needed, but this is not an auto logging cable, and the ABS's pink wire (found in the passenger's kick panel) will need to be interrupted (if ABS equipted).

 

[skifreee911]

i dont know anything bout electronics so ill just post a pic up tonight of it.

 

[mwreed]

I've had issues with my eBay cable. I ended up making a TTL to RS-232 cable with the instructions on MMCD's site. If you can find a friend who can solder and has some electronics knowledge, it can be pretty cheap. They do have a couple wires with the wrong pin numbers on them. I think it's the RX and TX lines to the DB9 connector are swapped. Mine works great now. I just don't have the greatest connectors, but, it's works.

Here is the site:

http://mmcdlogger.sourceforge.net

Here is the schematic:

http://mmcdlogger.sourceforge.net/schematics.gif

I hope this helps. I know my eBay cable was never stable and gave me incorrect readings... IE 255 counts of knock.

Mike

 

[skifreee911]

i couldnt get a good pic of it. but if you look at it from the top i guss, the side that has 5 pins instead of four. it goes black wire, skip a pin, red wire, then a resister or something off of the red wire to the fourth pin. there is also a resister or something in between the black wire and the red wire.

i know someone has had this problem.

 

[Red91Tsi]

I have a 91 AWD and I am putting together what I need for a logger. I plan on using either a m100 or m515. Not sure what if I want the color more or not.

I am also looking at getting this cable: eBay cable

It says 91-94 ALDL cable, question is will it work with my 91 (90 motor swap with ECU swap)

 

[funniegus]

I got a cable off of ebay also. Blasted thing is giving me 255 of counts also on stock boost.
I cant even pull codes either.

 

[neuro]

I got my cable off eBay a while back. I use it with mmcd on my '90 and have never had any problems. Maybe I'm lucky?

 

[steve]

Maybe I'm lucky?

Only that your cable works, not that it works with a '90. The OBD I loggers will work with 90-94 DSMs.

Steve

 

[boostcrazy92tsi]

i have a standard 1g logging cable and mmcd. it works on both of my 90 tsi and my buddies 91awd. check your cable connections on the aldl connector. it sounds like something might not be hooked up right. last but not least make sure u have the right cable. and the right kinda of sync cable. it has to b a serial cable for a palm and the palm has to have the right os.

 

[tom04841]

I bought a logger cable for my laptop, and it didn't work with 3 programs...tunerstein, TMO, or MMCD.

So I decided to remake the cable end since when i took off the casing the diode was backwards. This is what i did:

Pin 2: Diode anode
Pin 3: Diode cathode (banded end), end of resistor, and black wire (goes to pin 1 of harness)
Pin 5: Other end of resistor, and red wire ("Y"'d and goes to pin 10 and 12)

Guess what? STILL DIDN'T WORK

So i tried switching pins 2 and 3, STILL NOTHING!

What the hell is wrong?

 

[BoostedTalonTS]

Silly question:
Have you verified that your Serial ports are functional? Enabled in the CMOS on the laptop?
-Just a thought