A9. All operations stopped except mast lower. Line and steering contactor hold. If the key is turned on or the battery disconnect switch is reset right after the error, speed will be limited to 5km/h.

Possible causes are emergency power off, abnormal operation, harness fault, brake fault, emergency power off due to steering fault.

Trigger is either the keyswitch is turned off, battery disconnect switch pushed or the battery connector possibly disconnected while traveling at speeds over 2km/h. Can also set if traveling speed is over 2km/h when the parking brake is locked. Or if the truck enabled an emergency stop due to a steering fault.

To clear code - Turn power on
Wait 10mins with OUT operation (if truck is moved wait another 10mins).
Turn key off and on again
If a9 code persists after reset then it is a hard code and you must continue to diag.

Diag. - Must confirm code type with laptop service tool. After trying to reset.
If service tool says emergency power off then you have to perform an inverter discharge. Disconnect connectors E-01 and E-02 on the logic card and check continuity between E02-15 and E01-14. If there's continuity replace logic card of logic unit. NO continuity repair harness. Remember this is only for hard a9 codes that wont reset at all.

Common items that cause an intermittent code are the key switch and emergency stop button. Unicarrier (who owns the TXM truck that is a rebadged mitsi pretty much) recommends replacing both key switch and emergency stop button/red battery disconnect for intermittent codes first. Then further diagnosing into the harness if the code persist.

And a side note is the truck may not have a problem. Its possibly operator error by turning truck off or hitting the red button before they are fully stopped.