Thermistor Fault (P0A9C)

A thermistor fault is triggered detected if the analog voltage measured from the thermistor is outside of the normal operating range. This error can be triggered if the temperature of the thermistor rises above 80C or drops lower than -40C. A shorted or open wire can result in artificially high or low measurements that would result in this error code. Also the use of an incompatible thermistor can cause inaccurate readings and trigger this error code.

When this error code is set the Orion BMS will disregard the value of the affected thermistor and use the values of the remaining thermistors continue normal operation.

Resolving the issue:

Step 1) Check the thermistor wiring and ensure that the thermistors are wired properly. If the thermistor connector was not installed when the BMS was powered up, this error will result. Clear the error codes or restart the BMS if the connector was connected after the BMS was powered up.

Step 2) Check for any shorts on the thermistor wires. If the thermistors have been extended or modified then these areas would be the best place to check first.