Thanks, as of yet (this morning) my engineer on site has only checked for voltage at both forward and reverse contacts, which are the same, But..... the original fault he went to was the Line contactor dropping out intermittently when traveling in iether direction. The only rectification was to switch off and back on at ignition. I suspected a weak coil on the Line contactor but following a careful clean of all connections, the current fault manifested and the error code showed up for the first time. ?

Hi there

If you have voltage at the coil both negative and positive then the coil should energise unless you have an open circuit contactor coil. Check coil resistance against the forward contactor and see what the difference is.

Or mechanical fault on the contactor assembly itself.