1996 850 T5 ECU conundrum - OBD2 only talking to tranny

[esl_97_850_T5]

Sommerfeldt,

1. I think you answered them.

2. Why do you think "ISO 14230-4 KWP (5 baud init, 10.4 kbaud)" is the right protocol?
I'm presuming you left out the "2" in "14230".

It's true that I found a 14230 (and even a 15031) document useful in understanding the protocol used by my '97 850 T5.

However, as far as the ELM327 goes, the right protocol for talking to the '96-'98 850/S70/V70/XC70 is:
- ISO 9141-2 (5 baud init, 10.4 kbaud)
when performing OBDII emission diagnostics, and is:
- ISO 9141-2 (5 baud init, 10.4 kbaud)
preceded by a specific series of special ELM327 setup commands when intending to use the Volvo specific protocol which I call KWPD3B0.

That ISO 9141-2 -- whether for the OBDII emission diagnostics or the KWPD3B0 communication -- is most reliably setup using the ATSP 3 command [not the ATSP 4 command used to explicitly setup for ISO 14230-4 KWP (5 baud init, 10.4 kbaud)].

I've also found that ATSP 3A and ATSP A3 usually work -- but only if they end up using ISO 9141-2. But I now recommend ATSP 3 as the most reliable way to connect using ISO 9141-2, and therefore use it as the default in volvo850diag v0.7 (and later).

You can verify what protocol is used to connect successfully by issuing ATDP or ATDPN after the connection is established.

3. The 2 low cost solutions that I know of to read/clear your Motronic 4.3 DTCs are:

3a. Flashing LED tool using OBDII port's pins 3, 5, and 16.

For more info on the flashing LED solution, see:
- volvo_850_diag_links.html flashing LED tool links.

It should cost < US$10.

Don't let yourself be overwhelmed by the electronics. I'm also an electronics neophyte, yet was able to construct one in a few hours. I made a wise choice to use the 12V LED that had the resistor built in to it. That makes things a little simpler.

3b. Brick-Diag Free v0.0.6.6, talking to VAG/COM KKL FTDI USB cable, which is hooked to a cable which can selectively change OBDII pin 7 (from VAG/COM cable) to talk to OBDII pin 3 (on car's OBDII port) [see
this for an example of such a cable], and where the OBDII pin 7 switcher cable is hooked directly to the car's OBDII port so that the OBDII pin 3 communicates with the Motronic 4.3 using the KWP71 protocol. When using Brick-Diag Free v0.0.6.6 and selecting the "Motronic 4.3" ECU, you must use the "OBDII pin 7 switcher" cable to first switch it to pin 3 before you click the verbinden (ie, connect) button. Brick-Diag Free v0.0.6.6 will then be able to read the Motronic 4.3 DTCs. That's much easier than using the flashing LED tool. And you'll be able to clear the Motronic 4.3 DTCs. However, when you want to use Brick-Diag Free v0.0.6.6 to talk to the other ECUs (eg, AW 50-42, Kombiinstrument VDO / instrument VDO, Immo2 (850), ABS, SRS, E-sitz Links / Powerseat Left, E-size Rechts / Powerseat Right, etc.) during that same scanning session, you'll need to first use the "OBDII pin 7 switcher" cable to first switch back so pin 7 goes straight thru to pin 7 of the car's OBDII port. Or you could just totally remove the "OBDII pin 7 switcher" intermediate cable when dealing with the AW50-42, COMBI, ABS, SRS, etc).

For more info on Brick-Diag Free, see the 5 Brick-Diag oriented items in the list starting with:
volvo_850_diag_links.html Brick-Diag Free links.

This solution should cost < US$30.

The Brick-Diag Free v0.0.6.6 and "OBDII pin 7 switcher" cable solution takes more work to setup initially, but it's more convenient in the long run. Whether you decide to use 3a or 3b depends on how often you think you'll need to read/clear the Motronic 4.3 DTCs and if the cost differential and extra headaches to set it up matters to you.

4. Since you have a Scandinavian destined car which doesn't have USA-like flash updates which include the full '96 850 USA targeted OBDII emission diagnostics, I suggest you do not use the OBDII emission diagnostics protocol that reports DTCs as codes like P0172, P0133, etc, after being requested with the OBDII 03 and 07 requests and which clears those DTCs with the OBDII 04 requests. I'm presuming the reason you were not able to get Dash Command, Shift, and EOBD Facile working is your Motronic 4.3 just can't do substantive OBDII emission diagnostics. Also, for that reason I don't think Lee's Autel MS309 approach will work for your car (like it would for our USA cars).

Instead:

- for your Motronic 4.3 -- focus on using either of the just mentioned approaches: the flashing LED approach, or the Brick-Diag Free v0.0.6.6 with "OBDII pin 7 switcher" cable approach;

- for your other '96 850 T5 ECUs -- focus on using software or handheld tools that talk with the '96 850 T5 ECUs using the Volvo special KWPD3B0 protocol. [See a list of some of these software packages / tools in the next paragraph.]

5. Since you are presently focused on getting the Motronic 4.3 DTCs cleared so the Lambda / CHECK ENGINE light can be turned off, I'll not discuss the options for talking to the KWPD3B0-conversant ECUs, other than to mention some of the possibilities that have been mentioned on a bunch of topics both here at MVS and on several other Volvo forums:

- VST and VST-lookalikes (typically used by dealers and independent shops),
- cracked Vol-FCR v1.3,
- Brick-Diag Free v0.0.6.6,
- jonesrh.info's volvo850diag,
- Autel MS700 series and Autel MS800 series handheld scanners,
- Vol-FCR Full v1.7 (or later),
- Brick-Diag Full (for the privileged few that already have it),
- etc.

6. I don't think you'll be able to easily read the most commonly viewed, basic OBD live data (eg, short term fuel trim, long term fuel trim, etc) as you desire, since Brick-Diag Free doesn't allow displaying live data on any ECU (that I know of). But it may be possible with a bit of research, development, or ECU changes.

I seem to recall that some people have been able to read Motronic 4.3 live data using the MotronicSuite software. That might work for you. I don't recall having done this myself.

Alternatively, open source is available for the MotronicSuite software and for rkam's Volvodiag program that can talk using the Motronic 4.3's KWP71 protocol. So those are two options out there if you want to do some software development work yourself in order to see the M43 live data.

7. Even if you don't figure out how to read all the normal Motronic 4.3 OBD live data (that is viewable with USA targeted M43 ECUs), there's a small amount of OBD live data that you should be able to read on your Scandinavian '96 850 T5 via the COMBI (ECU 51) using the KWPD3B0 protocol:

- vehicle speed
- engine RPM
- engine coolant temp

The other COMBI-specific live data that can be read is:

- vehicle mileage
- engine hours since last SERVICE light reset
- low fuel status
- SERVICE light on status
- some other status flags (some of which can help determine if the engine is on)
- fuel level(s)
- ambient temp [only for the '98 S70/V70/XC70]
- some sort of fuel consumption value [only for the '98 S70/V70/XC70]

8. If you are absolutely insistent on reading your Scandinavian destined, original factory software, M43's OBD live data and you refuse to use or further develop some of the item 6 software yourself, you might consider:

8a. studying the OBDII wiring diagram for your car, buying a USA-targeted M43, and going through what is probably a non-trivial exercise to see if you can get the USA-targeted M43 working in your car, or

8b. converting your car to use a USA-targeted M44. I've now seen several (apparently) European cars that can perform USA-like OBDII emission diagnostics. I'm presuming this is European owners of European targeted cars that have M44 ECUs that have been reflashed with USA software. I've only started seeing this in the last few months. It might be a faulty assumption on my part, but it really does appear to be USA-style M44 with European-style COMBI data.

9. Can you detail how you get the ELM327 wifi dongle setup so it communicates to at least retrieve the single transmission PID. I don't recall seeing where anyone has successfully done this up to now. I was thinking about getting one myself to see if it could successfully be used, then document it. But if you have gone through the ground work already, can you describe the process (preferably in another thread which is specifically related to ELM327 wifi use with our 96-98 Volvos)? Preferably include some pictures or video. Or if it has already been documented elsewhere, include that link. Thanks in advance.

It might be best to delay that thread until after you successfully get some of the communication going to KWPD3B0-conversant ECUs. For example, you might show how to setup an ELM327 wifi dongle then use it to read the vehicle mileage from the COMBI. That would be a new and useful thread.

10. Where did you learn that "Anyhoo" used in the 1st post?

Digest the above in your own time and as your desire dictates. I'm in no hurry for any immediate answers to any questions I may have asked. I'm several months behind in my own work.

esl_97_850_T5