156 Strangeness

Mrs H called me from the supermarket car park.

The 156 was playing up:

Temp gauge in the red
Speedo wouldn't go above 20mph
Selespeed wouldn't change in City mode and wouldn't change above 2nd in
manual mode

I got there, the ABS warning light was on, the ASR was off and the
self-check told me we had a VDC(?) failure.

Fortunately, I had grabbed my NetBook and AlfaDiag cable.

15 mins later, having cleared the fault codes, re-calibrated Selespeed
and reset the main ECU, all was fine again.

Stupidly, I didn't make a note of the fault code, though.

Any ideas what may have caused it?

--
SteveH 'You're not a real petrolhead unless you've owned an Alfa Romeo'
Alfa 156 TSpark Sportwagon Veloce Selespeed - Alfa 75 TSpark Lusso
Ducati 750SS - BMW R100RT - Company Hack Focus TDCI

On Sat, 2 May 2009 13:41:29 +0100, (SteveH)
wrote:

>Mrs H called me from the supermarket car park.
>
>The 156 was playing up:
>
>Temp gauge in the red
>Speedo wouldn't go above 20mph
>Selespeed wouldn't change in City mode and wouldn't change above 2nd in
>manual mode
>
>I got there, the ABS warning light was on, the ASR was off and the
>self-check told me we had a VDC(?) failure.
>
>Fortunately, I had grabbed my NetBook and AlfaDiag cable.
>
>15 mins later, having cleared the fault codes, re-calibrated Selespeed
>and reset the main ECU, all was fine again.
>
>Stupidly, I didn't make a note of the fault code, though.
>
>Any ideas what may have caused it?

<lots of guessing>

An ABS sensor? Vehicle dynamic control will, I suspect, be using these
in conjunction with an accelerometer somewhere and fly-by-wire
throttle inputs - maybe braking inputs too. I doubt it's much to do
with the Selespeed although the Selespeed will control the throttle
(downshifts etc). I wonder if the Selespeed (in a fault condition) can
issue stupid throttle commands that upset the ECU and/or VDC system.
Might be worth looking at whatever detects accelerator position too.
I, also, believe the ECU and VDC are separate computer systems with
VDC being part of the ABS package. Plenty of interconnections and
interactions to check there... :-(

However, temp gauge in the red?? Was the engine actually overheating?
If so and/or the ECU has decided the engine was overheating would it
have told everything to go into serious limp home mode - hence the VDC
failure. It wouldn't surprise me if VDC (as a safety system)
complained if the ECU told it VDC could only have limited/no throttle
control?

Dunno.

</lots of guessing>

Someone who knows what they're talking about might be along shortly!
It sounds like a very good Alfa specialist would be the thing if it
happens again.

--
Z
Scotland
Alfa Romeo 156 2.4JTD Veloce Leather
'Oil' be seeing you..
(Email without 'Alfa' in subject will be auto-deleted..sorry!)

It can be just one sensor giving a faulty signal, of the severity that
causes the ecu to go into a "limp home" mode with restrictions on revs,
gears etc.
Rod

"Zathras" > wrote in message
...
> On Sat, 2 May 2009 13:41:29 +0100, (SteveH)
> wrote:
>
>>Mrs H called me from the supermarket car park.
>>
>>The 156 was playing up:
>>
>>Temp gauge in the red
>>Speedo wouldn't go above 20mph
>>Selespeed wouldn't change in City mode and wouldn't change above 2nd in
>>manual mode
>>
>>I got there, the ABS warning light was on, the ASR was off and the
>>self-check told me we had a VDC(?) failure.
>>
>>Fortunately, I had grabbed my NetBook and AlfaDiag cable.
>>
>>15 mins later, having cleared the fault codes, re-calibrated Selespeed
>>and reset the main ECU, all was fine again.
>>
>>Stupidly, I didn't make a note of the fault code, though.
>>
>>Any ideas what may have caused it?
>
> <lots of guessing>
>
> An ABS sensor? Vehicle dynamic control will, I suspect, be using these
> in conjunction with an accelerometer somewhere and fly-by-wire
> throttle inputs - maybe braking inputs too. I doubt it's much to do
> with the Selespeed although the Selespeed will control the throttle
> (downshifts etc). I wonder if the Selespeed (in a fault condition) can
> issue stupid throttle commands that upset the ECU and/or VDC system.
> Might be worth looking at whatever detects accelerator position too.
> I, also, believe the ECU and VDC are separate computer systems with
> VDC being part of the ABS package. Plenty of interconnections and
> interactions to check there... :-(
>
> However, temp gauge in the red?? Was the engine actually overheating?
> If so and/or the ECU has decided the engine was overheating would it
> have told everything to go into serious limp home mode - hence the VDC
> failure. It wouldn't surprise me if VDC (as a safety system)
> complained if the ECU told it VDC could only have limited/no throttle
> control?
>
> Dunno.
>
> </lots of guessing>
>
> Someone who knows what they're talking about might be along shortly!
> It sounds like a very good Alfa specialist would be the thing if it
> happens again.
>
> --
> Z
> Scotland
> Alfa Romeo 156 2.4JTD Veloce Leather
> 'Oil' be seeing you..
> (Email without 'Alfa' in subject will be auto-deleted..sorry!)

"SteveH" > wrote in message
. ..
> Mrs H called me from the supermarket car park.
>
> The 156 was playing up:
>
> Temp gauge in the red
> Speedo wouldn't go above 20mph
> Selespeed wouldn't change in City mode and wouldn't change above 2nd in
> manual mode
>
> I got there, the ABS warning light was on, the ASR was off and the
> self-check told me we had a VDC(?) failure.
>
> Fortunately, I had grabbed my NetBook and AlfaDiag cable.
>
> 15 mins later, having cleared the fault codes, re-calibrated Selespeed
> and reset the main ECU, all was fine again.
>
> Stupidly, I didn't make a note of the fault code, though.
>
> Any ideas what may have caused it?
>
> --
> SteveH 'You're not a real petrolhead unless you've owned an Alfa Romeo'
> Alfa 156 TSpark Sportwagon Veloce Selespeed - Alfa 75 TSpark Lusso
> Ducati 750SS - BMW R100RT - Company Hack Focus TDCI

After much thought, the answer : "it's an Alfa Romeo".

Dave S.... 156 2.0 SP2 1998 :>)
--
It's only rock 'n' roll ....

Old programmers don't die - they just abend 0C4.