Reading Codes - Page 2 - PeachParts Mercedes-Benz Forum

JimF · #16 08-05-2003, 06:22 PM

between the high end stuff, AST Retriever and the LED/Sw combo (biuld it yourself) DIYer tool.

The Retreiver costs $2300 making it, to my mind, a high price tool. Would love to have one since it can do LIVE data, reading the S/A (self adaptation), firing/mis-firing, O2, MAF data, etc.

The PS just reads and resets codes from 1988 thru 2002. It does not do what any LIVE data. I'm sure the SnapOn device probably does that but not familiar with it.

Actually, the newest/latest versions have added such goodies as a 'scope' which you would appreciate. Then you could "see" the misfire. But if it is failing (even intermittantly), the Retreiver would catch it in the LIVE data mode. But for me, the price is just too high.

I would stay away from just OBD scanners as Steve suggests; if it can give Mercedes type codes and OBD, then ok.

I've use the PS and it's a good tool taking its limitiations in mind. The PS is great deal for the price (send me an email). Depends on what you NEED to do.

wjm · #17 08-05-2003, 07:51 PM

OK, I got it built... but I just noticed I got the wrong connectors put on the ends. I thought the tiny 3/32 Mono phone plugs would fit into the holes of the 38 pin (X11/4) diagnostic connector.. I was wrong.

I just noticed that on the module that has the LED display, there is a spot that I can tie into the #1 and #3. I tested it and it has just under 12 volts, so that must be tied directoy to the X11/4. I can use the banana plugs for those.

I'll have to figure out how to get the 3rd plug (yellow) into the x11/4... maybe I can use something thin like a paper clip and then use an alligator clip (in place of yellow) to grab the clip.

wjm · #18 08-06-2003, 07:42 AM

Let me rephrase my last question.

Can I use banana clips for + (red) and - (black) and connect them to the X11/21 (LED connector) #3 and #1 respectively? This is not the X11/4 38 pin connector.

Also, what do you recommend I use for the yellow (test) connector that gets plugged into the X11/4 connector? (ie... #23 for testing Alarm DTCs). The only though I had was to stick a staightened out paper clip in the hole and use an alligator clip on the test wire.

JimF · #19 08-06-2003, 10:53 AM

you planned 'attack' looks ok to me. Pin #1 (ground) and Pin#3 (12V) will be just 'dandy' to use.

Need to get a pin that will fit nicely into the holes without damaging the pin. Check some surplus electronic houses in your area and look for some old pins from military connectors. You should be able to find one that will fit nicely.

But if a paperclip works, then use it. Would suggest that you solder it and then use a bit of shrink sleeving, so just the tip is exposed; just enough to stick into the pin under test.

GeneN · #20 08-06-2003, 12:15 PM

I've build Jim's LED/switch for my 1994 C280 with the 38 pin connector. I used male pins from an RS-232 connector. They fit the 38 pin diagnostic connector in the C280. They are available at Radio Shack, as are the other parts.

As previoulsly suggested, solder and heat shrink the pin to wire junction.

I did have a problem with reading some codes, the voltage at the pin was not +12 volts, but varied from +9 to +10 volts. Couldn't get a code read from those pins, but the rest worked OK.

I was able to read and clear the codes and solve several problems. My mechanic even came up with the same codes when he corrected the problem.

wjm · #21 08-06-2003, 02:16 PM

Jim and Gene,

Thanks!

The RS232 pins are an EXCELLENT IDEA! As a computer geek, I'm surprised I did not think of that earlier. Thanks again.

Jim,

Based on your website, below are 10 different "systems " that I check codes for. Each one uses a different pin on the X11/4. Is this true? Are these all available to my 94 E420 (California)? Any others that I'm missing?

Distributor Ignition Module [DI] DTCs
Diagnostic Module [DM] DTCs
Hot Wire, Sequential Fuel Injection Module [LH-SFI] DTCs
Base Module [BM] DTCs
Electronic Accelerator/Cruise Cntrl/Idle Speed Cntrl Module [EA/CC/ISC] DTCs
Anti-lock Brake System w/ Acceleration Slip Regulation Control Module [ABS/ASR] DTCs
Supplemental Restraint System [SRS] DTCs
Anti-Theft Alarm System [ATA] DTCs
Convenience Features [CF] DTCs
Automatic Air Conditioner [A/C] Operational Check and Diagnostics DTCs

KAMAL · #22 08-06-2003, 02:49 PM

I can't seem to find 0.1 amp fuse for circuit. I am using 0.25amp. Can somebody verify that if it is ok to use .25amp fuse for the led box.

thanks

wjm · #23 08-06-2003, 03:40 PM

The newer design I used did not have an inline fuse.... so I did not add one. I might have if I could have found the right fuse. Also, Radio Shack sells 12volt LEDs now, so there is no need for the resistor.

JimF · #24 08-06-2003, 08:23 PM

I even know the pin numbers without looking then up!!

Distributor Ignition Module [DI] DTCs = 17
Diagnostic Module [DM] DTCs = 19
Hot Wire, Sequential Fuel Injection Module [LH-SFI] DTCs = 4
Base Module [BM] DTCs = 8
Electronic Accelerator/Cruise Cntrl/Idle Speed Cntrl Module [EA/CC/ISC] DTCs = 7
Anti-lock Brake System w/ Acceleration Slip Regulation Control Module [ABS/ASR] DTCs = 6
Supplemental Restraint System [SRS] DTCs = 30
Anti-Theft Alarm System [ATA] DTCs = 23
->Convenience Features [CF] DTCs = 21 but not your car<-
Automatic Air Conditioner [A/C] Operational Check and Diagnostics DTCs = 16

wjm · #25 08-06-2003, 10:42 PM

Thanks Jim,

I'll have to make sure that those map the same to my car... I think it's in alldata... but you're probably right.

Oh yea.. by the way... the built in LED blinks along with the the one in the unit I built... so I really don't need the LED... I could just use a diode.

I have quite a few codes. Will have to look them up.

Pin 6 -- 13,25,26
Pin 7 -- 7, 11
Pin 8 -- 9, 10, 11, 12, 13
Pin 30 -- 4

Now I know that 30 is the SRS.. and 4 probably comes up because I recently took out the passenger air bag when I replaced my aspriator motor.

I have the convenience feature in my car.. why can't I get codes from that module?

JimF · #26 08-07-2003, 10:38 AM

Here's what my DTC Manual says for your DTCs.

Pin 6: ABS
13 - Brake Lamp Switch
25 - Left front vehicle speed sensors
26 - Right front vehicle speed sensors

Pin 7: EA
7 - CAN data bus signal from EA, ABS, LH-SFI control module faulty
11- Closed Throttle recognition signal to engine control module, LH-SFI. Fuel safety shut-off to engine control module, LH-SFI

Pin 8: Base Module
9 - Voltage supply for LH-SFI control module interrupted
10 - Same as above plus voltage supply for fuel-injectors interrupted
11 - Voltage supply for accessory equipment control module interrupted.
12 - Voltage supply for ABS or ABS/ASR or ASD control modules interrupted.
13 - NOT USED ???

Pin 30: SRS
4 - Right front ETR squib

Interesting codes! I quess you had no codes in the other modules since you didn't post any other module?

The SRS is a DIGITAL module so surprised you got codes from it.

Convience Features are reserved for the '140' car, so don't know what that pin is??? Are you sure it's '30'??

How's your wiring harness???

I would reset all of the codes and then see what comes back in a few days.

wjm · #27 08-07-2003, 10:48 AM

Jim,

Those were the only pins that returned a code.

I started putting together a worksheet of codes. First page has all of the readable pin locations and subsequent pages have codes for each pin.

I'm making my list using your site and comparing it to what alldata shows. I guess i'll check my CDs as well. There indeed are some subtle differences between your codes (which I assume are for the 140) and the 124. I'll be more than happy to send you the excel spreadsheet once I'm done.

Yes, I did get a 4 from Pin 30. And, it make sense... as I did take out my airbag recently to change the aspirator motor.

Again, my 94 E420 does indeed have the convenience feature module (I believe below the rear seat on driver side).... so why would I not be able to get codes out of it? Are codes only generated out of that module for a 140?

Also, I wonder if speed sensors codes are being generated because I replaced my wheels/tires with slightly larger ones?

BTW... harness was replaced in January , 2001

I will reset all of the codes and try again in a few days.

FUN STUFF FOLKS!!!

wjm · #28 08-07-2003, 12:45 PM

I just checked my 38 pin connector. Many of the pins don't have any contacts in them. Here are the 13 that do:

1,2,3,4,6,7,8,13,14,16,17,19,30

1-Ground
2-Voltage, circuit 87 or circuit 15z
3-Voltage, circuit 30
4-LH sequential multiport fuel injection, Engines 104,119
6-Anti-lock brake system, Electronic traction system, Acceleration slip regulation, Electronic stability program
7-Electronic accelerator, Cruise control/idle speed control
8-Base module, Brake assist
13-TNA-signal (gasoline), LH-SFI engines
14-On-off ratio, Engine 119 LH-SFI, Engine 120 LH-SFI (right)
16-Air conditioning, Models 124, 140, 202, 208, 210
17-Distributor ignition, Engines 104, 119, Engine 120 (right)
19-Diagnostic module (USA)
30-Airbag/ETR (SRS)

Of those (excluding 1-3 which are ground and voltages), only 2 have no matching DTC table (13 and 14). Does anyone know those are monitored?

Also interesting is that I don't have a pin in 23 which is supposed to monitor the Anti-Theft Alarm System. Any clues?

wjm · #29 08-07-2003, 04:04 PM

OK, According to ALLDATA (well.. a posted Mercedes Service Bulletin), looks like #14 is used for lambda reading.

When I hooked up my DIY LED reader's test plug to #14 (with black in #1 and red in #3), the LED lit up without even pushing the button. This tells me that it was an active ground. Needless to say, I did not push the button, as I was afraid of shorting something out.

Still trying to find out what #13 is used for. Anyone? Description is TNA-signal (gasoline), LH-SFI engines. I get no return signal with my DIY LED tool.

JimF · #30 08-07-2003, 08:04 PM

done a pin mapping of X11/4 and that's why you said your car had CF (pin 21). So I quess you hadn't.

See my page, MENU#4 re Lambda testing. I have the M0039 meter and use it measure the car's lambda. But you can accomplish this testing with any meter that has duty cycle. Others have used a Fluke meter: do a search and you'll find alot of info on it.