What Does This Error Mean?

E-bike gears not shifting properly are most often caused by derailleur cable stretch or a bent derailleur hanger. Adjust the barrel adjuster at the rear derailleur by half-turn increments until the shift is clean under load.

Affected Models

E-bikes with Shimano gearing
E-bikes with SRAM gearing
Aventon Pace series
Rad Power RadCity
Trek Allant+ series

Common Causes

Derailleur cable stretched over time, reducing shift precision
Rear derailleur hanger bent from a fall or hard impact
Cable housing cracked or kinked, adding friction to the shift
Chain worn — skips on cassette sprockets under motor torque
Derailleur limit screws set incorrectly causing over-shifting or under-shifting

How to Fix It

Adjust the barrel adjuster.

The barrel adjuster is the small cylinder where the gear cable enters the rear derailleur. If gears are slow to shift to larger sprockets, turn the barrel adjuster counter-clockwise by half a turn. Test and repeat in half-turn increments until shifting is smooth under pedaling.
Check the cable for kinks or damage.

Run your hand along the full length of the gear cable and housing from the shifter to the derailleur. A kinked or frayed section adds uneven friction that makes shifts slow and imprecise. Replace a damaged cable and housing at a bike shop.
Inspect the rear derailleur hanger.

The hanger is the small aluminum tab connecting the derailleur to the frame. Look at it from directly behind the bike — if it angles inward or outward instead of pointing straight down, it is bent. A bent hanger causes systematic misshifting and needs professional straightening or replacement.
Check for chain wear.

E-bike chains wear faster than regular bicycle chains due to the additional motor torque. Use a chain wear indicator — if the chain has stretched more than 0.75%, replace it along with the cassette. A worn chain skips under motor load even when the derailleur is perfectly adjusted.
Re-index the gears from scratch.

If multiple adjustments have not resolved the problem, fully re-index the gears. Shift to the smallest sprocket, loosen the cable anchor bolt, pull the cable hand-tight, and retighten. Then use the barrel adjuster to fine-tune until all gears shift cleanly without skipping.

When to Call a Professional

If the hanger is visibly bent or the derailleur is cracked, take the bike to an e-bike or bicycle shop. Hanger alignment requires a specific tool, and bent hangers should be replaced rather than straightened.