ELM329
Error Messages and Alerts (continued)
LV RESET
STOPPED
The ELM329 continually monitors the 5V supply to
ensure that it is within acceptable limits. If the voltage
should go below the low limit, a ‘brownout reset’ circuit
is activated, and the IC stops all activity. When the
voltage returns to normal, the ELM329 performs a full
reset, and then prints LV RESET. Note that this type of
reset is exactly the same as an AT Z or MCLR reset
(but it prints LV RESET instead of ELM329 v2.0).
This low voltage protection is not only necessary
for the ELM329 to operate properly, but it also offers
protection for the CAN transceiver ICs too. Most
transceiver chips require a minimum operating voltage
of 4.5V, while some require a minimum of 4.75V.
If any OBD operation is interrupted by a received
RS232 character, or by a low level on the RTS pin, the
ELM329 will print the word STOPPED. If you should
see this response, then something that you have done
has interrupted the ELM329. Note that short duration
pulses on pin 15 may cause the STOPPED message
to be displayed, but may not be of sufficient duration to
cause a switch to low power operation.
The message is printed any time that an OBD task
is interrupted.
UNABLE TO CONNECT
The ELM329 has tried all of the available
protocols, and could not detect a compatible one. This
could be because your vehicle uses an unsupported
protocol, or could be as simple as forgetting to turn the
ignition key on. Check all of your connections, and the
ignition, then try the command again.
NO DATA
The IC waited for the period of time that was set
by AT ST, and detected no response from the vehicle.
It may be that the vehicle had no data to offer for that
particular PID, that the mode requested was not
supported, that the vehicle was attending to higher
priority issues, or possibly that the filter was set so that
the response was ignored, even though one was sent.
If you are certain that there should have been a
response, try increasing the ST time (to be sure that
you have allowed enough time for the ECU to
respond), or restoring the CAN filter to its default
setting.
?
This is the standard response for a misunderstood
command received on the RS232 input. Usually it is
due to a typing mistake, but it can also occur if you try
to do something that is not appropriate for the protocol.
<RX ERROR
An error was detected in the received CAN data.
This most often occurs if monitoring a CAN bus using
an incorrect baud rate setting, but it may occur if
monitoring and there are messages found that are not
being acknowledged, or that contain bit errors. The
entire message will be displayed as it was received (if
you have filters set, the received message may not
agree with the filter setting). Try a different protocol, or
a different baud rate.
SEARCHING
This will be displayed when a message has been
provided for transmitting, but a protocol is not yet
considered to be active. When displayed, it means that
the ELM329 is searching for an appropriate protocol to
use. Similarly, the message may be displayed if the IC
is directed to monitor the data bus, and there is no
protocol active.
ELM329DSB
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