10 and 15 second delay in response from WIU/TIU

Every once in a while, the WIU/TIU delays either 10 or 15 seconds before it responds.

I used Wireshark to watch the WiFi packets and I can see these pauses. I can get the 10 second delays by changing the speed repeatedly. I can get the 15 second delays by accessing the trip odometer or chronometer repeatedly.

Here is a partial Wireshark trace. Packet 887 arrives 15 seconds after packet 886.

No.     Time          Source          Source Port    Destination           Port       Length Info
    885 15:42:33.376 192.168.1.120         64215       192.168.1.122         32768         57     q\r\n
    886 15:42:33.414 192.168.1.122         32768       192.168.1.120         64215         60     [ACK]
    887 15:42:48.397 192.168.1.122         32768       192.168.1.120         64215         78     TIU response failure\r\n->
    888 15:42:48.411 192.168.1.120         64215       192.168.1.122         32768          57     q\r\n
    889 15:42:48.412 192.168.1.122         32768       192.168.1.120         64215          60     [ACK]
    890 15:42:48.422 192.168.1.122         32768       192.168.1.120         64215          76     q00 01 6B 60  okay\r\n->

I've seen this with two different WIU/TIU devices.