On Board Computer 964, tank Autonomy
#1
On Board Computer 964, tank Autonomy
My name is Jorge.
From 4 weeks ago, I´m the owner of a nice 964 C4 year 92. My car has on-board computer all functions working properly, except the autonomy, always indicate 999 km.
maybe you can help me, since I´m completed lost.. any point to check
I appreciate your support
Regards and thanks in advance
Jorge
From 4 weeks ago, I´m the owner of a nice 964 C4 year 92. My car has on-board computer all functions working properly, except the autonomy, always indicate 999 km.
maybe you can help me, since I´m completed lost.. any point to check
I appreciate your support
Regards and thanks in advance
Jorge
#5
And I thought it was my lack of english language skills that fooled me...
I guess the tachometer does not receive the tank signal, is your fuel gauge working properly? It could also be a faulty Load Signal from the engine management unit that makes the tacho able to determine the fuel consumption. It could also be a faulty memory chip in the tachometer.
Cheers,
Tore
I guess the tachometer does not receive the tank signal, is your fuel gauge working properly? It could also be a faulty Load Signal from the engine management unit that makes the tacho able to determine the fuel consumption. It could also be a faulty memory chip in the tachometer.
Cheers,
Tore
#6
Thanks for you comments
Exaclty I want to say the distance to empty, always indicate 999 km.
Yes the fuel gauge is working property. I understand that inside the tank must be some sensor to send the signal to OBC, do you know where I can find?
Regards and thanks
Jorge
Exaclty I want to say the distance to empty, always indicate 999 km.
Yes the fuel gauge is working property. I understand that inside the tank must be some sensor to send the signal to OBC, do you know where I can find?
Regards and thanks
Jorge
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#8
I think you have stumped the entirety of rennlist. This is the first of this issue I have ever heard of...
In fact, I had no idea our cars had any indication of miles to empty.
Help us understand. How did you come across the problem, and what have you tried already to find a solution. This way maybe we can check things off the list...
In fact, I had no idea our cars had any indication of miles to empty.
Help us understand. How did you come across the problem, and what have you tried already to find a solution. This way maybe we can check things off the list...
#11
hmm, very odd. Have you disconnected the battery - leave it disconnected for say half hour, try again?
Have you read the manual? Maybe there is a way to reset this?
Does your fuel gauge read correctly?
I never use mine, but last time I looked, it worked ok.
Have you read the manual? Maybe there is a way to reset this?
Does your fuel gauge read correctly?
I never use mine, but last time I looked, it worked ok.
#12
Yes is very odd.
Sure I disconnected the battery, still the same issue.
In the manual nothnig about this
the fuel gauge works property.
Is there inside the tank a sensor to measure this? or some mechanism that send the signal to the OBC
Regards
Sure I disconnected the battery, still the same issue.
In the manual nothnig about this
the fuel gauge works property.
Is there inside the tank a sensor to measure this? or some mechanism that send the signal to the OBC
Regards
#13
My educated guess on the operation of this feature is the OBC compares (remaining fuel)/(current consumption rate) and comes up with (km to empty). I don't know if the OBC uses the calculated fuel economy (ltr/100km) that it calculates separately or some other fuel usage measurement but I am pretty sure that there is no separate sensor in the fuel tank for this. I have not seen this problem on my OBC so I don't have much more to add. Does your fuel economy display number make sense?
#14
The tacho contains a EEPROM memory that can fail. This may well be the case here, especially if the tank signal is OK. The tachometer OBC computer may be having problems reading/writing from/to the memory, thus the faulty display reading.
You could try the instrument in a different 964 or 993 with OBC, and see if the instrument behaves better there. If not, you have to get your OBC fixed.
Cheers,
Tore
You could try the instrument in a different 964 or 993 with OBC, and see if the instrument behaves better there. If not, you have to get your OBC fixed.
Cheers,
Tore
#15
Any idea of what type of MCU the tach is using and/or do you have any front & back pictures of the pcb?