P0908: Gate Select Position Circuit A Intermittent

What does P0908 mean?

Points to a gate select position signal on circuit A that drops out or jumps for short moments in an automated manual gearbox, too briefly or too irregularly for a steady low or high fault. Loose terminals, a damaged harness that moves with the engine, or moisture in the connector at the shift and select actuator are the usual reasons. No manufacturer documents this code publicly. An Aisin AI patent explains why even short sensor dropouts matter: if a stroke sensor fails while driving, the controller can no longer confirm the engaged gear and must switch to a fallback strategy. CARB requires circuit and rationality checks on such inputs. P0904 to P0907 are the steady faults of the same circuit. Drivers often notice occasional neutral drops or refused shifts that vanish again.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Warning light that comes and goes
• Occasional drop to neutral or refused shift
• Fault often disappears after restarting the engine

Common causes

• High Loose or spread terminals at the sensor or actuator connector
• Medium Harness damage that only opens or shorts under engine movement
• Medium Moisture or corrosion in the connector near the gearbox

Likelihood is a general estimate across vehicles; your make and model may differ.