ELM329
Error Messages and Alerts
The following shows what the ELM329 will send to
warn you of a condition or a problem. Some of these
messages do not appear if using the automatic search
for a protocol, or if the Programmable Parameter bits
disable them.
ACT ALERT
DATA ERROR
This message occurs as a warning that there has
been no CAN or RS232 activity (ie commands or
messages received) for some time, and the IC is about
to go to the low power mode in one minute. If an input
signal is found during that minute, the switch to low
power will be cancelled.
There was a response from the vehicle, but the
information was incorrect or could not be recovered.
<DATA ERROR
There was an error in the line that this points to,
either from an incorrect checksum, or a problem with
the format of the message (the ELM329 still shows you
what it received). There could have been a noise burst
which interfered, possibly a circuit problem, or perhaps
you have the CAN Auto Formatting (CAF) on and you
are looking at a system that is not of the ISO 15765-4
format. Try resending the command again – if it was a
noise burst, it may be received correctly the second
time.
This message may be disabled by setting PP 0E
bit 3 (RS232) or PP 0F bit 5 (CAN) to ‘0’.
BUFFER FULL
The ELM329 provides a 512 byte internal RS232
transmit buffer so that OBD messages can be received
quickly, stored, and sent to the computer at a more
constant rate. Occasionally (particularly with some
CAN systems) the buffer will fill at a faster rate than it
is being emptied by the PC. Eventually it may become
full, and no more data can be stored (it is lost).
If you are receiving BUFFER FULL messages,
and you are using a lower baud data rate, give serious
consideration to changing your data rate to something
higher. If you still receive BUFFER FULL messages
after that, you might consider turning the headers and
maybe the spaces off (with AT H0, and AT S0), or
using the CAN filtering commands (AT CRA, CM and
CF) to reduce the amount of data being sent.
ERRxx
There are a number of internal errors that might be
reported as ERR with a two digit code following. These
occur if an internally monitored parameter is found to
be out of limits, or if a module is not responding
correctly. If you witness one of these, contact Elm
Electronics for advice.
One error that is not necessarily a result of an
internal problem is ERR94. This code represents a
‘fatal CAN error’, and may be seen if there are CAN
network issues (some non-CAN vehicles may use pins
6 and 14 of the connector for other functions, and this
may cause problems). If you see an ERR94, it means
that the CAN module was not able to reset itself, and
needed a complete IC reset to do so. You will need to
restore any settings that you had previously made, as
they will have returned to their default values.
CAN ERROR
The CAN system had difficulty initializing, sending,
or receiving. Often this is simply from not being
connected to a CAN system when you attempt to send
a message, but it may be because you have set the
system to an incorrect protocol, or to a baud rate that
does not match the actual data rate. It is possible that
a CAN ERROR might also be the result of a wiring
problem, so if this is the first time using your ELM329
circuit, review all of your CAN interface circuitry before
proceeding.
LP ALERT
This appears as a warning that the ELM329 is
about to switch to the low power (standby) mode of
operation in 2 seconds time. This delay is provided to
allow an external controller enough time to prepare for
the change in state. No inputs or voltages on pins can
stop this action once initiated.
If you are seeing these messages while working
with the CAN silent mode off, then return to CAN silent
mode (AT CSM1). There is likely a problem with your
baud rate.
ELM329DSB
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