DRB II Help--Making the SCI Cable, Need Pinouts

One thing I had not considered.

OTC transitioned from a 12V POS battery clip on the DRB-II to using an AUX Port "cigarette lighter" style plug on all their later diagnostic scanners.

That could get awkward if your sitting in the vehicle to get power and can't reach the SCI connector in the engine compartment.

If you get the Bestek 12 V battery clips to AUX port adapter, you can hook-up to the battery direct while in the engine compartment and forgo using a vehicle AUX Port "cigarette lighter" style plug port.

That will also ensure the DRB-II gets the "cleanest" and "quietest" 12 V GND connection possible in the vehicle as it will be coming straight out of the 12 V battery DC.. with no losses due to a poor ground at all.

The only essential part in the design is the DRB-II connector to the DB-25 Male part, which would cost 16.84 in parts by itself. That could be tested and provided as a special cable or I hesitate to say it an "adapter".. OTC really should think about sourcing just this piece, they could sell more of the parts they already provide. I kind of wish I knew some manufacturers that could provide just that part.

Another thought is this design uses more "connectors" but that adds to the reliability.. when a cord gets jerked or yanked.. the DRB-II doesn't go flying across the room.. or the "Expensive" DB-25 splitter cord doesn't get all caught up in the engine fan.. you only loose the tiny part at the tail end.. like a "gecko lizard".. I kind of like the multi-connector cable aspect.

byghtn said:

The OTC setup gave you an 8-foot(?) extension cable for the 8-pin din cable...

Thanks for fleshing this tester/topic out!:thumb:

Click to expand...

The OTC 3305-72 DB-25 Power and 8-Pin DIN is 96 inches long (US) or 8FT from the Female DB25 connector to either the Female 8-Pin DIN or the AUX Port Power Plug.. if you divide the two cables up and stretch them so each cable is its full lenth that is a total of 192 inches or 16FT [ I just measured it with a tape measure to be absolutely accurate ]

The OTC 212635 Chrysler SCI Connector to 8-Pin DIN is effectively 10.5 inches from the seated base of the SCI plug to the seated base of the 8-Pin Male DIN connector that would add on to the length of the OTC 3305-72 but I usually wouldn't count that as really significant.

The 839-1067-ND Digi-Key 8-Pin Male DIN to 6 ft shield cable adds 6FT from the DB25 (so) the longest length is either 6Ft + 8FT from the DRB-II connector to the AUX Power Port or 6FT + 8FT from the DRB-II connector to the SCI connector.

Both DRB-II units I have encountered have a 32 inch cord from DRB-II body to seated base of its 8-Pin Female DIN connector.

(all measurements just rechecked) so I'm not quoting from some datasheet.

I really should learn how to use a wacom tablet to draw.

Hmm.. I could sketch and scan it in like some other people have done though.

lol.. i haven't had my hands on a pencil in at least 12 years!

Well not much more progress to report at this time.

I spent the Holiday (in the US its Memorial day) looking into low cost drafting, illustrating and paint software.

I also have an old (really old) Fujitsu fi-4220C flatbed and feeder scanner which fujitsu refused to release an driver to support Windows 7 because they said it was too old. At first I went the stubborn way and was gonna figure it out.. but long term I wanted to get it back on the "supported" road. I purchased a copy of VueScan (basic) which has a CalTech, Voyager mission alumni backing it (for over 20 years)(and his son has joined the company.. so 20 more?) and over 2000 drivers for old scanners.. highly recommended if you get in the same bind. That's how I scanned in the pages from the DRB-II Operators Manual for Friday nights Video.


I have an old Wacom Bamboo 670 tablet from work that I decided to finally learn how to use (not the least was the concepts of how those even work with a modern computer.. it ain't easy folks).

Then spent time learning to use the wacom with Inkscape (Adobe Illustrator clone), Artweaver (Photoshop clone) and DraftSight (Autocad clone).. each like the real thing has a "best use case".. and I knew next to nothing about them at 8 am this morning... its been a quick day.

All of this is so I can better document this "Cable adapter" and the hopefully subsequent "Cheaper Cable".. because if I only do it one-time it doesn't really benefit anyone else.

After all of that I think Inkscape will be the most useful. DraftSight is for doing technical drawings (like Autocad makes).. Inkscape is for doing technical illustrations (like Illustrator makes).. Artweaver is for touching up photos or drawing freeform works of art very far from reality (like Photoshop makes). At one end stands the needs of the "mechanical engineer" at the far end stands the needs of the "lyrical poet".

There are render engines that bridge the technical drawings into high-fidelity illustrations, even movies.. but that's overkill for what I plan to do. And I didn't have time today to finish learning Blender or even look at sculptris.

Something North of a shakey freehand drawings is all I'm looking at.. perhaps starting by tracing over a few photographs of parts and embellishing them.. looks to suit my goals. It looks like a lot of people generally do that anyway.

I'm rebuilding a fuel pump module for the D250 RAM truck I'm going to test the OEM engine cable and new engine Cable on.. but I had to stop to get some o-rings or beveled washers to fit the fuel pump supply, return and drain tubes. That's another story.. but basically the existing ones had degraded because of the increasing ethanol in the fuel supply and materials in 1989 did not expect to be attacked by ethanol.. so had to get some aircraft Buna-N grade o-rings.. because I have no idea how to get Buna-N beveled washers for these tubes. When I reassembled the fuel module the first time it wouldn't hold a pressure seal.. so I digress.. but all of this is preliminary and explains whats holding up more precise diagrams and testing.

.. oh.. and I'm lucky to have a Day job that needs attention tomorrow too.

Maybe I'll have something useful to post soon.

This is a confirmation of the connections between pins in the 8-way (DIN) connector to the 6-way (SCI) connector and the 12 V battery clamp on the original CC2000 engine cable, for anyone who builds their own and wants to make sure they have an identical cable before trying to use it.



The test was performed using a Multimeter in continuity mode, an alligator clip clipped to each SCI blade in turn and a test probe to each DIN Pin in succession.

Ohms were not measured, only continuity, a tone served to confirm a connection and a + was inserted in a green box in the chart.

I count six "must make" connections.

NOTE The sketch and picture below are of an actual OEM CC2000 DRB-II cable. No swapping of sides or compensation for DRB-II Connector "view" versus Cable "mirror view" are required. Simply make sure the continuity follows the chart and measure continuity from "DIN8 connector pin -to- SCI connector pin". (I think it should be obvious DIN8 Pin1 "does not" connected to SCI Blade Pin1.. thats what the chart is for.. )

NOTE I've noticed some tiny "raised pin labeling in plastic" on the SCI connectors from Actron and OTC which do not correspond to Chrysler labeling in the sketch from the DRB-II Operators manual. The chart above is in "Chrysler pin labeling" as in the sketch below.

NOTE I've noticed the wire color chart for the DIN8 pre-wired cable does not appear to be quite accurate. Be sure to complete the cable by verifying the continuity. (I have not tested this home made cable on a vehicle and a DRB-II yet.. but if continuity is the same as the OEM cable I would expect it to work.) And be sure you understand no guarantees or implied warranties from me.. if you decide to make your own cable.. you accept full responsibility for any problems that might occur.

NOTE I also checked the available continuity of the [ OTC 212635 Chrysler SCI Connector to 8-Pin DIN ] not all of the SCI blade pins are connected to a DIN8 Pin, specifically, SCI Blade pin #4 which is used for obtaining NEG or GND is not brought out. The SCI Connector is effectively a solid plug of plastic, so it cannot be brought out. That means using OTC parts, ground will have to come through the AUX Port power connector (the "cigarette lighter" connector). Which is fine if your using the AUX Port inside the vehicle, or you get one of those Bestek AUX Port female to POS and NEG battery terminal clamps for working entirely under the hood. The alternative is if you use the OTC 212635 SCI connector without the DB25 cable, you'll have to splice in both a POS and NEG battery terminal clamp to power the DRB-II. Otherwise it should be fine. [This will probably make more sense when I finish my diagram.]

Looking into the future ...

After this OTC cable I'm thinking of a less complicated cable although it may take a little more skill to assemble.

The DIN8 is a standard connector DIN 45326 / IEC/DIN EN 60130-9

Its been around a long time and is commonly used in Marine and the Music industry. As such splitter cables are not that rare.

The Clarion - Marine Remote Control Y-Cable looks as if it could be paired with an OTC 212635 Chrysler SCI Connector to 8-Pin DIN and a couple of battery terminal clamps to provide POS and NEG.

One of the female branch connectors would be removed.. and the redundant wires connected to battery terminal clamp wires.

Or a male DIN8 connector shell could be built up with just the battery terminal clamps connected and plugged into one of the branches.

Meanwhile the Male connector appears to be a DIN8 assembled housing which means it might be possible to dissassemble it and re-wire it to support the OTC cable on one female end and the battery terminal clamps on the other end.. to provide the connections the DRB-II needs.


Marine Remote Control Y-Cable for Select Clarion Receivers and Remotes

OTC 212635 12' Standard 6-Pin Adapter Cable for Chrysler

Tips A few tips for powering up the DRB-II.

#1 It "must" have a cartridge installed. I frequently take mine out for storage. If you power it up without a cartridge it will not beep (as is normal) it will not flash the screen as it tests the display. It will do absolutely "nothing" to confirm that it is alive. It will act completely "unconnected" from a power source. It will play "dead".

#2 The cartridge "contacts" can become oxidized or corroded over time. They are made of some type of copper or copper alloy which produces a grayish "non-conducting" surface over time. And each time you insert and remove them the DRB-II pressure contacts "rake" their sharp edges over the contacts re-exposing them to air.. so I'm not sure storing them outside the DRB-II is a good idea. It depends on how the DRB-II is stored and whether the case its stored in will let you leave the cartidge in place. If the cartridge is inserted and the DRB-II plays "dead" you might try wiggling or cleaning the contacts and re-inserting it. (note: I always disconnect power before inserting or removing a cartridge)

#3 The DRB-II is an "old" computer, it takes a relatively "long time" to show signs of "life". After its powered up it will take a full 3-6 seconds before it even "beeps" and then will begin its self-test, which will consist of the beep, flashing the LEDs green and red in the center of its "chest" and then testing the display.. and finally start displaying legible characters on its display.. all this.. "getting ready" to start displaying the Cartridge ID and Version.. [before] it gets around to displaying a menu. I tend to think of it like that old Lost in Space robot on TV.. its got a lot of character.. and can be a bit cranky at times when you "wake it up".

Another Tip and cable progress

#4 Putting a "Non" Super Cartridge in like a V6.0 for a specific year, will not communicate with your vehicle if its not of that year. I have a 1989 Dodge D250 and I connected to and as soon as it identified the vehicle it said "you will not be able to communicate with this vehicle, install a 1989 cartridge" (so) version updates are not "rolling or cummulative" updates where cartridges are concerned. A Very unexpectant but good thing to know! Fortunately I also had a Super cartridge and it did cover that year. [ Its only a guess, but EEPROMs and EPROMs from that time were somewhat expensive and small.. only years later did they get bigger and could hold everything. They might also have offered a higher tier of cartridge that cost more and supported everything.. I don't know for sure.. but the result is Super Cartridges are much more useful ]

I got to test my DRB-II and OEM cable on a vehicle this weekend. But didn't have the OTC based cable ready. The heatshrink and soldering of four connections just took more time than I could manage. Put together the black shell and DB25 connector look pretty good, but its getting those four connections soldered that take a lot of care.

I was suprised the SCI connector was so hard to put onto the engine compartment SCI/DLC connector. I had noticed some evidence of releasing compound in the SCI connector of the OEM cable.. but thought it was more to protect the longevity of the plastic.. I now believe it was more to prevent jerking and pulling excessively on the cables coming out of the SCI connector.. I could easily see how the OEM cable might be destroyed over time by pulling on them too much.

Regardless of how you make a cable this could be a problem.. so some type of non-corrosive lube that won't hurt the plastic but won't affect the contacts is probably something you want to consider.

Also the SCI connector in the engine compartment doesn't have a cap to prevent road dirt or moisture or anything else from getting into its contacts. Not a great situation. So you might want to consider coming up with some type of protective cover.

I was amazed however to see it worked and the DRB-II had no problems communicating with the engine.

cadman777 said:

jwillis84,

Did you ever get your cable figured-out?

I just got a DRB II w/Jeep-Eagle adapter, but need the SMEC 6-pin cable to diagnose an '88 Horizon, but can't find one.

So if you know, would you be so kind as to show me what pins connect from the DIN 8 to the SMEC 6 and to the battery clamp? I'd be very grateful, since it seems I need to make my own cable at this point.

Cheers ... Chris

Click to expand...

I think I have.. I have the parts and the pins to connect.

I just have to solder the final cable together, I lost some momentum to finish because I have been busy with other things.

But after it is finished I need to test it before I will post the final construction blueprints (as it were).

Since I got my truck running, and have used the OEM cable I acquired.. its also been distracting me. I've gone from a no pressure fuel pump situaiton, to a replaced fuel pump and then an over pressure situation.. which led to replacing the pressure regulator.. so now I'm back to a Lean running condition. It's nice to have a DRB-II talking to me to tell me what the computer thinks is going on. I can also see the difference in the O2 sensor thanks to the DRB-II. So.. since the DRB-II won't capture or graph the data.. I'm looking at Scan GTI and the OTC 4000E.

In effect I'm graduating to studying fuel trims.. but a guess is I'm searching for a vacuum leak now.

Having a true set of diagnostic tools like the DRB-II and OTC 4000E are night and day different from using a volt ohm meter and guessing in the dark. But having realtime graphs and saving data to study later is really important too.

cadman777 said:

Thanx for getting back to me.
Glad to hear you're having success.
What is "scan gti"?
I know about the Monitor 4000E.
How is it better than the DRB II?
I thought it was limited in what it could read, and in not being able to send feedback signals?

Click to expand...

OTC is the original vendor/maker/(inventor?) of the DRB-II which was sold under the Chrysler brand.

They went on after the DRB-II to produce an entire line of diagnostic tools they sold under their own name, and which closely paralleled the original DRB-II

The DRB-II was for Chrysler products [only] and tailored to work with them, whenever Chrysler tried something "different" in the next years car, Chrysler updated the DRB-II.. where OTC more or less played catchup.

Where OTC excelled is they added support for other car makers, like Ford, GM and others. They aren't "better" than the DRB-II and are not mentioned at all in the Chrysler diagnostic service manuals.. for diagnostics Chrysler only supported the DRB-II.. but the OTC could still communicate on the same wires and extract data.

Scan GTI was a software package for Windows 3.1 and Windows 95 which also works on Windows XP. It could be run on a laptop or computer, then connected with a cable to the top of the OTC 4000E, which was virtually identical to the DRB-II "port wise". Scan GTI will not communicate with a DRB-II.. but it can with an OTC 4000E.

Scan GTI can then "read" live data from the engine computer and store it in a file and/or graph it on a live graph to show the values and how they change over time. And it can take recordings and produce "graphs" later.

One of the things different about having a DRB-II is you have a choice of looking at the "Sensors" actual voltage readings as the computer sees them, and as the computer interprets them. So a temp sensor might be at 1.1 volts the computer can tell you that, and then it can also tell you what that means to it 119 degrees Farenheit. So you know whether the computer is getting the right signal, and whether its doing the calculation to interpret it right.

It can also tell you if the computer thinks the engine is running "RICH" or "LEAN" which is important.. because if the computer thinks its running "RICH" it will shorten the interval the injector valves are open to release less fuel.. but if the problem is "over pressure" like my new fuel pump was producing.. it can't compensate in extreme cases.. and continues to run "RICH".. which is bad.. for fuel economy and for the catalytic converter.. and it can flood the engine.

So once that's fixed the computer can tell you.. running "LEAN" which means its trying to keep the injectors open longer to mix enough fuel with all the extra air a vacuum leak will let in.

The thing is when a computer makes a decision it remembers it and sets a new normal called a "TRIM" which is an offset it assumes is needed to keep the engine alive. You can't see what that is without a DRB-II or OTC 4000E, let alone graph it.

Graphs are useful because when you experimentally rev the engine a leak will be less and less significant and the fuel TRIM will start to fall.. so you can confirm thats the problem. Other problems will show up as different curves.. like signatures.. and steer you in the direction of the problem.

I'm just an amateur at this.. so I've still a lot to learn.. but that's where I am now.

One other thing (among many) sensors can produce "patterns" in their output, like the O2 sensor swinging from high to low rapidly, that's normal and good.. a dead sensor will just be stuck high or low. A speed distance sensor should produce a pulse train the computer can measure to determine speed and signal the transmission or the engine to prepare for a gear shift.. you really can't see a lot of things like that without a scope or recording the values and graphing them.. which is what really made it hard to work on cars when all the electronics sensors began to get installed on vehicles.

But that was way back as far as the 1970's... today.. having all this data means a car could in theory be diagnosed much faster.. if the owner had access to these tools and a smart program.

I ramble on a lot.

But the key bit is the OTC 4000E can generally "read" anything from a Chrysler, Ford or GM vehicle that's where its speciality resides. But the DRB-II knows all the secret codes for turning stuff off and on, like solenoids (called actuators) and checking switch states (on/off). Those are important too.. but when diagnosing an engine usually not as important.. they're more for checking a relay, or turning a light off and on.. or wiping a code from the computers memory. The DRB-II are relatively "rare" because they were for Chrysler products [only] the OTC 4000E and its cousins were more generic and more were made.. so on ebay they go for a whole lot less money.

Acquiring a DRB-II was difficult but acquiring an OTC 4000E was a lot easier and less expensive. Further the cables for an OTC 4000E are still being made and sold on Amazon and eBay. So there are good reasons for having both.

One of the things that gets lost in the conversation though is without proper adapter boxes (like you have) or the right cartridge.. you may have a DRB-II but not the software to talk to your vehicle. Back in 1989 (remember Atari and TRON?) software was either on cassette tapes or hard plastic game cartridges.. minature 5 inch floppy disks were still in the future.. the first cartridges only covered one year of vehicles at a time.. none of the vehicles for the year before.. and none for the year after.. you bought a new cartridge for every year. Later the "Super cartridges" came out and covered all the vehicles for multiple years.

cadman777 said:

Nice write-up!
Thanx for the info.
Where'd you learn about diagnosing and all that?
I used to be very good at a/c diagnosing and carburetors, b/c I initially had charts to show me what gauge readings meant. Eventually, experience added to the charts. But all this computer stuff is new to me. I've been out of the loop since the late 80's, when I was a Honda tech. Wish I could find something that would get me started. I'm a mechanical guy, not an electrical guy, which makes it harder to learn, b/c this stuff is taught to people who can memorize tons of trivia and then pull from it whenever they need to, whereas I'm the kind of brain that needs standards, procedures and ordered logic to diagnose.
Know of anything that may get me started right?
I have the service manuals, but they are about as good as a Philadelphia brick.
What I would like to have is a manual that has flow-charts and procedures, like the HELM manuals I've used.

Click to expand...

Well.. my background is computers.. in the 80's I couldn't do video games because they gave me motion sickness.. so I focused on fixing games and setting them up for other people. So that's how I got into computers, more in the head than sitting in front of them. I missed learning about cars for the most part but my Dad passed away and left a really old truck that needed repair.. a 1989 Dodge D250 pickup.. and it was the first year an Electronic Fuel Injected system was put into it.. so its pretty simple compared to everything before and since. Its a sweet spot of just complicated enough and demonstrates but not too much.. a lot of stuff was put on this vehicle for the first time.

I bought the factory service manuals.. studied them.. and like you remained baffled.. the B&W diagrams covered several models and weren't very specific (each book covered lots of vehicles) and no where near photographically accurate. The parts catalog at over a 1000 pages was a little more helpful.. but not with theory.. how things worked.

So I then turned to getting a few parts, a few tools.. and happened across a DRB-II on ebay.. then an OTC.. then found the Scan GTI software.. and a few YouTube channels.

One of which is below.

There is a lot of attitude to most of anything you find online, and some of it can be wrong, but by taking it slow and verifying what I learn. I think my education is going okay.

I'm motivated not by a critical deadline, but by the memory of my Dad.. and that sort of keeps me going.

The Dodge forums and the Allpar site had a lot of good info.. just not always easy to find.

Matt on the YouTube channel has a ton of videos, long and detailed about "how things work" he makes fun of people in a hurry to change parts or who don't really care how something works. Which kind of bugs me.. but for the most part he seems to make a lot of sense. In small doses I really do enjoy his videos.

I guess I should also mention I'm a diagrams type of guy, at work I use visio to draw out just about everything. So that Matt draws on his whiteboard alot really helps. And there are a lot of animations on YouTube about things like Throttle Bodies, Injectors, PCV valves, EGR valves, Fuel Tank Vapor valves and air valves.. and someone always seems to write them up on Wiikipedia with drawings.

I liked the history about PCV valves.. coming from World War I and they were replacements for "Draft Tubes" and a freebie "gift" to the car industry by Cadillac. EGR valves have a similar story behind them, and Vapor Canisters.. they all had a reason in history for coming into being.

The "pointless" distributor was also fun to learn about.

No "Really".. its "pointless".. because they introduced a Computer to run the spark coil and timing.. and it was all doodled up and put together by one technician in an amazingly short period of time all by himself.. all our cars run on them today.

The sensors that ran the computer were thunk up first for improving reliability.. then improving gas mileage.. and then reducing emissions.. most people thought it was the other way around.. lots of sweeping history in the car in the last 50 years. Its interesting.