What Error 423 Means

Error 423 indicates that the drive unit detected an unstable or failed battery connection. The Bosch drive unit performs a battery authentication handshake on every power-on cycle. If the contacts are dirty, the battery is not fully seated, or the BMS is not responding, error 423 is triggered and motor assistance is disabled.

Genuine battery required: Only genuine Bosch PowerTube and PowerPack batteries pass the authentication check. Third-party replacements always produce error 423.

Causes

  1. Battery not fully seated — The most common cause. If the locking mechanism has not fully engaged, contacts may not be reliable.
  2. Dirty or corroded contacts — Gold-plated contacts accumulate dirt and oxidation over time.
  3. Damaged contact pins — A bent or broken pin prevents a complete circuit.
  4. BMS deep-discharge protection — A deep-discharged battery whose BMS is in protection mode fails authentication.

Fix Procedure

Step 1: Remove and Reinstall the Battery

Unlock the battery fully, clean both battery contacts and frame strip with a soft cloth. Reinsert firmly until the locking tab clicks into locked position.

Step 2: Clean the Contacts

Apply electronic contact cleaner to a cotton swab and clean each contact pin. Allow to dry fully before testing.

Step 3: Inspect for Bent Pins

Inspect all contact pins on the frame strip under good lighting. Badly damaged contacts require replacement by a dealer.

Step 4: Charge the Battery Fully

A BMS in deep-discharge protection produces error 423. Connect the battery to its charger for a full charge cycle before retesting.