ECU recordings

ECU recordings

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lotus211

Original Poster:

2,961 posts

157 months

Friday 4th October 2013
quotequote all
Help me understand- does the ecu record all previous faults and failures over the cars history and not just record mileage, operating hours and revs etc?

Rockster

1,492 posts

132 months

Friday 4th October 2013
quotequote all
lotus211 said:
Help me understand- does the ecu record all previous faults and failures over the cars history and not just record mileage, operating hours and revs etc?
The ECU records any fault along with some data (freeze frame data) associated with the fault. The fault can be cleared using a scan tool or by letting the ECU clear the fault after so many engine start/warm up cycles with the fault not being present.

I do not think the ECU has an archive of old (and cleared) faults and fault data.

As for over rev events, only the most recent event time (in engine run time) is retained along with the count of the number of total events. There is no way I know of to get a history of over revs, say the number of events and event time.

Now I have to point out that Porsche can of course log or record or archive whatever it wants to and it does log/record/archive a bunch of stuff. This stuff is based on what I've been told and sort of observed is under certain cases downloaded from the ECU (and other controllers) and bundled up and sent to Porsche.

I'm not sure when this is done. That is certain services, say related to warranty issues, may require this be done. But bring your car in for say just an oil/filter service maybe not, probably not, unless the service engine now light wants to be cleared. This I understand requires the diagnostics computer be connected and a full scan made of the car's electronics systems/controllers. At this time data of interest is read from the vehicle and sent over a proprietary network to Porsche.

Or bring the car in for a problem that requires the diagnostics computer be connected to check for say security module errors and a full scan of the car's electronics systems/controllers is done, and the data is shipped to Porsche. The tech then of course has the security alarm scan info with any error codes, or fault codes, etc. that can help point him towards the cause for why the car was brought in in the first place.

lotus211

Original Poster:

2,961 posts

157 months

Friday 4th October 2013
quotequote all
Ok many tks. So if a warning light appears on the dash for a problem does this get recorded on the cars ECU ?
Just curious as to how these things work. My readout on my car is spot on and clear rev ranges but that's all the readout states

Pope

2,519 posts

219 months

Saturday 5th October 2013
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A fault will be stored in a memory with specifics around the fault to enable diagnosis; a snapshot of pertinent data is collated and stored - temp/revs/date/time/load/runtime/throttle inputs/emission data and lots more - any OBD reader can extract the data from the main ECU's (specifically in the USA as OBD faults can be checked at the roadside and a car taken off the road (please correct me Rockster?))

The VAL or Vehicle Analysis Log that Rockster refers to is a complete collection of the above and should be downloaded from the car each visit to a centre - Ferrari have a similar regime. The Log contains runtime data, 'Actual' values, conditions and Adaptation and coding data where relevant from all ECU's on the vehicle (DME, Instrument Cluster et al) the data can be used to pinpoint adaptation trends and enables worldwide comparison for system improvements and also reference for technicians to aid fault diagnosis. Most ECU's have volatile memories that can be erased / cleared with use or with a battery disconnect but there are also units that are non-volatile. The latest cars have more units with Permanent Fault memory sections - particularly linked to emissions and engine running conditions. Instrument clusters on 1997> cars can store info on distance driven with check light on and time/mileage with low oil pressure but cars as early as 928 with digi dash did that much earlier.



Edited by Pope on Saturday 5th October 00:19

lotus211

Original Poster:

2,961 posts

157 months

Saturday 5th October 2013
quotequote all
Great tks for info

Rockster

1,492 posts

132 months

Sunday 6th October 2013
quotequote all
Pope said:
A fault will be stored in a memory with specifics around the fault to enable diagnosis; a snapshot of pertinent data is collated and stored - temp/revs/date/time/load/runtime/throttle inputs/emission data and lots more - any OBD reader can extract the data from the main ECU's (specifically in the USA as OBD faults can be checked at the roadside and a car taken off the road (please correct me Rockster?))

The VAL or Vehicle Analysis Log that Rockster refers to is a complete collection of the above and should be downloaded from the car each visit to a centre - Ferrari have a similar regime. The Log contains runtime data, 'Actual' values, conditions and Adaptation and coding data where relevant from all ECU's on the vehicle (DME, Instrument Cluster et al) the data can be used to pinpoint adaptation trends and enables worldwide comparison for system improvements and also reference for technicians to aid fault diagnosis. Most ECU's have volatile memories that can be erased / cleared with use or with a battery disconnect but there are also units that are non-volatile. The latest cars have more units with Permanent Fault memory sections - particularly linked to emissions and engine running conditions. Instrument clusters on 1997> cars can store info on distance driven with check light on and time/mileage with low oil pressure but cars as early as 928 with digi dash did that much earlier.



Edited by Pope on Saturday 5th October 00:19
Right except that "OBD faults checked at the roadside and the car taken off the road" part. AFAIK, no state or any other jurisdiction has any rules/laws about a car with OBD2 faults. Now of course, with a simple code reader one can read the codes at any time and based on the codes can decide to take the car off the road to avoid subjecting the engine to serious damage.

Oh, wait, maybe you were referring to emissions testing in which if the car fails due to DTC or readiness monitors not complete can be denied a registration and an unregistered car can not be insured and should not be driven with no insurance. Like everyone obeys that law...

Anyhow, there's "in-use" data and it can be a lot. "20 pages" is what a tech told me when I asked how much data was collected and sent over. In the past I have received a page or two of this data the page or pages that pertain to a specific question or issue regarding my car. I've never received the entire printout and I'm not sure with the newer diagnostics computers the data can be printed. To know specifically what data Porsche was interested in... well, I would think Porsche would consider that business proprietary.

But one can guess: Porsche (like every other car maker) uses every vehicle as a test platform and uses it to gather real world in-use data to better know how its cars are used, how they perform, and to collect a bunch of telemetry about the car, its engine, and other systems.

About all Porsche doesn't collect is location data from the NAV. Collecting that would be based on my info illegal.

mikem7709

961 posts

184 months

Sunday 6th October 2013
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As far as I'm aware, once a fault code is erased (even with a simple generic reader) that's it, providing of course the fault isn't still present.

I do wonder wether its possible for manufacturers to partition off somewhere to permanently store the data but even then it would only be a matter of time before somebody figured a way to remove it.


lotus211

Original Poster:

2,961 posts

157 months

Sunday 6th October 2013
quotequote all
Turns out that any fault that appears on the dash gets logged in the ECU immediately so upon a service/inspection a technician can address the fault then when the issue with the car is sorted they can clear the data. Or after something like either 40 turns of the ignition key the data will be cleared though this bit may be inaccurate and is unclear. What however he did say was that if for example you replace the battery then all fault lights that have appeared on the dash will clear from the ECU providing the fault no longer exists.

agtlaw

6,006 posts

178 months

Sunday 6th October 2013
quotequote all
lotus211 said:
Turns out that any fault that appears on the dash gets logged in the ECU immediately so upon a service/inspection a technician can address the fault then when the issue with the car is sorted they can clear the data. Or after something like either 40 turns of the ignition key the data will be cleared though this bit may be inaccurate and is unclear. What however he did say was that if for example you replace the battery then all fault lights that have appeared on the dash will clear from the ECU providing the fault no longer exists.
Disconnect battery terminal and the 'fault' may go. We did this to a mate's GT3 which would occasionally show CEL. My obd reader showed it as a lambda sensor.

Don't think the ECU stores historic faults. If anyone has a definite answer then I'd be interested.