I am experiencing an issue with my Cargo BT Series 12 forklift. The forklift is unable to move forward, although the forks can still be maneuvered.

The error codes displayed are:

* When a gear is engaged: 26 56 89
* In neutral: 88 56

When I raise and lower the forks, the error codes clear and I am able to move the forklift forward and backward.

Do you have any idea what might be causing this problem?

Thank you for your assistance.

Best regards,