When the following error codes are output, bit 2 is set in the ESR register.
| Error code | Explanation |
| -400 | Query error |
| -410 | Query INTERRUPTED
The query was interrupted. Example: a query is followed by new data before a response was completely sent. |
| -420 | Query UNTERMINATED
An incomplete query was received. Example: the device is addressed to talk although the received query was incomplete. |
| -430 | Query DEADLOCKED
A condition causing a DEADLOCKED query error occurred. Example: both input and output buffer are full and the device can not continue. |
| -440 | Query UNTERMINATED after indefinite
response
A query was received in the same program message after a query requesting an indefinite response was execute. |