smartmaniacs.co.uk/forum/the-cars/fortwo-450-sept-1998-oct-2007/863740-3-bars-and-can-t-run-gear-adaptation

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Forum thread: Announcement

smartmaniacs.co.uk/forum/the-cars/fortwo-450-sept-1998-oct-2007/863740-3-bars-and-can-t-run-gear-adaptation · p. 1 · Applies to: 450

Source: smartmaniacs.co.uk Topic: drum rotation sensor corrosion and gear adaptation failure Models discussed: 450 Language: en Solution status: yes

Problem: 2003 Smart 450 Passion 700cc with fault codes P2022 (Clutch system fault) and P203C (Actual position of turning angle sensor); gear change adaptation fails and car shows 3 bars and won't start after attempted repair of transmission cable.

Solution: Replaced faulty drum rotation sensor (part number 0003254V009) with unit from donor 2007 vehicle after cleaning corrosion from transmission bore and applying water-repellent grease; gear change adaptation then completed successfully.

Key facts: - Drum rotation sensor (0003254V009) is used only for diagnostics and gear change adaptation, not for normal operation - Water ingress caused white aluminium oxide corrosion on rivet connection between pin 1 and resistor, rendering sensor inoperable - Gear position during normal operation comes from two-channel encoder built into gear change motor, allowing car to run with sensor disconnected - Faulty drum rotation sensor prevents successful gear adaptation and results in 3 bars and engine start failure - Prevention requires cleaning corrosion products from transmission bore and applying protective water-repellent grease during reassembly