Re: [opendiag] Re: How to communicate with a ECU

Nigel-
do you have throttle body?
i sort of had the same error on my 96 jetta.
i would reset the error, think it was gone, and then
wham! on startup there she was again.
it turns out ****carefully**** and ****thoroughly****
cleaning the inside areas of the throttle body with
carb cleaner
cured this error (especially where the throttle plate
rotates on it's shaft through the body).
what happens is that there is so much oil/gas black
gunk that the idle circuit has trouble fighting the
gunk upon startup and goes to max idle (at limit)
which causes a fault.
give 'er a go governor!

--- nigel.webb@... wrote:
> Bole,
> Well, what can I say but WOW!
> This I see as really good information that nobody
> wanted to talk
> about. On behalf of the group, or at least myself
> may I say thank you
> very much, got any more ? :)
> Now I have had time to look at my notes for the
> error codes listed I
> can tell you I had 4 errors at this time.
> 18010 Battery….
> 17916 Idle Control system, upper regulation limit
> reached 35-00
> 17967 Idle speed….
> 1182 Altitude adaptation…
>
> FC 46 5A A3 45 FC 23 46 2F A3 04 9E 90 was correct
> Does this help Bole ?
>
> The reason for the errors was, I found a broken
> "breather hose" from
> the side of the engine to throttle housing. Fixing
> this cleared all
> the errors but one. "17916" this keeps coming back.
> I would be
> grateful if anybody could shed some light on what it
> could be causing
> this error.
>
> The battery fault was because it had been
> disconnected in the recent
> past, (before somebody asks me or points out that a
> breather hose has
> very little to do with voltage supply)
>
> Has anybody got information on communicating with a
> Rover 214 MEMS
> ecu?
>
> Nigel
>
>
>
>
> --- In opendiag@y..., "Veselinovic Bozidar"
> <vescomp@s...> wrote:
> > hi nigel and others,
> > if you excuse my englisch, i'll try to explain
> some of the (BASIC)
> stuff in doing comms with the ECU,
> > but first a word to Jeff: Please, don't leave
> this group,
> reconsider it and let us all ( and I mean ALL )
> > try to make something usefull.
> >
> > OK, here it is:
> > 1. Tester sends 5baud ECU-adress - it doesn't
> matter if 7 or 8
> bits, eighth bit is consider as stopbit, ok ? ;)
> > That's why the address cant't be > 7FH - and
> stopbit or
> deadline is the same...Hey folks, think a bit...
> > 01=ENGINE, 02=TRANSMISSION, 03=BRAKE, and
> so on...
> > 00= This is the spec. adress, meaning
> INTERROGATE ALL FAULT
> MEMORY
> >
> > 2. ECU ( should ) reply with sync-byte ( 55H ) -
> as You have noted,
> 1's and 0's are alternating -
> > it's very easy to compute BAUDRATE. ( But, no
> need for this -
> VW is doing all at 9600baud -
> > OBDII / KWP2000 do comms at 10400 - here is
> why: no matter
> which frequency CPU uses,
> > ERROR at 10400 baud is allways less than 4%. (
> 5% is some
> reasonable limit, as CPU must
> > check linestate min. twice for a bitperiod ).
> >
> > 3. Tester now sends ( at computed BAUDRATE, 8bits,
> 1stop,
> noparity )
> > 55H + KEYWORD( LSB - MSB 01H - 8AH )
> >
> > 4. ECU replies with complement of 8AH = 75H
> >
> > 5. Now, Tester and ECU exchanges BLOCKs ( ECU
> first )
> >
> > 5a. Every BLOCK consists of:
> > a) BLOCK length - 1 Byte
> > b) BLOCK counter - 1 Byte (
> wraps around )
> > c) BLOCK title - 1
> Byte ( command )
> > d) BLOCK message - 1..255
> Bytes
> > e) BLOCK end - 1 Byte
> ( 03H )
> >
> > 5b. Some of BLOCK titles are following:
> >
> > 05H - CLEAR ERROR-codes
> > ** Any stored ERRORs will be cleared - send
> command 07H
> (READ ERROR) immediatilly after,
> > to see if ERRORs are cleared.
> > 06H - END communication
> > ** ending communications - means: untill now
> You was
> connected to: AIRBAG-ECU for example,
> > but if You want to communicate with other
> ECU, issue this
> command and repeat from step 1.
> > Or, You want to exit TEST-procedure
> correctly, as a gentleman.
> > 07H - READ ERROR-codes
> > ** ERROR-codes are received all in one
> BLOCK- if no ERRORs
> are stored, 00-00-00 is received.
> > 08H - SINGLE reading ( CHANNEL nr. is in
> BLOCK message )
> > ** read DATA that ECU can provide: AIR-TEMP,
> ENGINE-TEMP,
> RPM...
> > returns raw DATA, the way to convert the data
> is not supplied
> ( in GROUP reading is).
> > 09H - ACKNOWLEDGE received BLOCK
> > ** Keep the communications alive, means: At
> the present
> moment I don't need anything from You,
> > but stay on... It's the TESTER PRESENT
> command in KWP2000
> protocol.
> >
> > F6H - BLOCK consists of ASCII-data
> > FCH - BLOCK consists of HEX-Data
> >
> > Block data that You received at beginning seems ok
> - should be ECU-
> ID and COMPONENT.
> > SOFTCODING and WORKSHOPCODE should follow, evtl.
> ADDITIONAL INFO,
> after that TESTER can
> > start communications with ECU.
> > So far, everything is OK, but...
> > You got the following ERROR-codes --- how ?
> > ECU 0F (15 bytes to come)
> > PC F0 (ack 0F)
> > ECU 15 (line no 15h)
> > PC EA (ack 15)
> > ECU FC 46 5A A3 45 FC 23 46 2F A3 04 9E 90 ( ***
> see below ***)
> > PC (all bytes acknowledged by the PC as they came
> in)
> > ECU 03 (end of transmission - transfer control to
> other
> > party?)
> >
> > Let's see:
> > ECU FC
> > ^
> > HEX_DATA follows
> >
> > ECU FC 46 5A
> > ^^^^
> > 18010 (P1602) Power Supply (B+) terminal 30 Low
> Voltage = ERROR 1
> >
> > ECU FC 46 5A A3
> > ^^
> >
> INTERMITTENT
>
> = ERROR 1 / elaboration
> >
> > ECU FC 46 5A A3 45 FC 23
> > ^^^^^^
> > 17916 (P1508)---Unknown Trouble Code
>
> = ERROR 2
> > Unknown
> elaboration
>
> = ERROR 2 / elaboration
> >
> > ECU FC 46 5A A3 45 FC 23 46 2F A3
> >
> ^^^^^^^
> > 17967 (P1559) Idle speed
> controller =
> ERROR 3
> >
> INTERMITTENT
>
> = ERROR 3 / elaboration
> >
>
=== message truncated ===

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Received on Tue Jun 05 12:11:05 2001