Bosch E-Bike Error Codes Complete Guide: All Codes, Symptoms, and Repairs

Your Bosch e-bike communicates faults via a set of clicks from the drive unit. The number of clicks tells you the error code. Below are all 36 codes, what they mean, the likely causes, and exactly what you can fix at home versus when to call a dealer. No fluff—just the diagnostics you need to get back on the road.

Quick Lookup Table

Earliest Checks Before You Look Up a Code

Before you jump into code-specific fixes, do these three quick steps. They solve about 30% of intermittent errors without any tools.

1. Check the battery connection. Remove the battery, inspect the metal contacts on both the battery and the bike mount. If they look tarnished, clean them with a dry cloth or isopropyl alcohol. Reinsert firmly until you hear a click.

2. System reset. Turn off the bike, remove the battery, wait 60 seconds, then reinsert and power on. This clears many transient errors (like Code 511 after a minor bump).

3. Inspect the speed sensor. The sensor is a small plastic tab near the rear wheel spoke magnet. The gap between sensor and magnet should be 2–5 mm. If it’s wider or the magnet is missing, adjust or replace.

Branch: After reset, if the error disappears and doesn’t return, you’re good. If the same code reappears within a few minutes, proceed to the code-specific section below. If you see no code but the motor still cuts out, check the wiring harness for a pinch or loose connector (common on Code 606).

Featured Error Codes – Detailed Diagnosis

These codes are the most common failures on Bosch e-bikes. Each entry includes a concrete fix, evidence of why it happens, and a clear stop point.

Code 610 – 6 Clicks

• Symptom: Motor stops completely, no pedal assist.
• Cause: Internal motor winding short or open circuit. The controller detects a shorted phase and cuts power instantly.
• Evidence: This is the most common internal motor failure on older Bosch drive units (pre‑2020). A winding short usually happens after prolonged high-torque climbing in extreme heat.
• Fix: Requires motor replacement. Do not open the motor case—high‑voltage capacitors can hold a charge. Take it to an authorized Bosch dealer.
• Stop point: If you measure continuity across motor phases with a multimeter and see zero ohms, stop all DIY attempts.

Code 510 – 6 Clicks

• Symptom: Motor stops, error recurs even after reset.
• Cause: Motor control unit failure—typically a blown MOSFET or damaged driver chip. This is a logic‑level fault, not a wiring issue.
• Evidence: On Performance Line CX motors, this code appears after a sudden wheel lock (e.g., brake jam) that sends a voltage spike back into the controller.
• Fix: Replace the entire drive unit. Simple resets will not clear this. Only a Bosch diagnostic tool can verify the failure.
• Tool needed: Bosch diagnostic tool (dealer only). Do not attempt to repair the PCB yourself.

Code 640 – 5 Clicks

• Symptom: Motor stops, pedal resistance feels uncharacteristically high (like riding with brakes dragged).
• Cause: CAN bus communication breakdown between battery and motor. The motor goes into a safe mode with high magnetic resistance.
• Fix: First, clean battery mount contacts with isopropyl alcohol. If that doesn’t work, update firmware via dealer. The communication protocol is sensitive to dirt and voltage dips.
• Branch: If cleaning resolves it but the code returns after a few rides, the battery BMS may be failing—monitor the error frequency. Replace battery if it repeats weekly.

Code 503 – 2 Clicks

• Symptom: Motor stops, error reappears every time you try to ride.
• Cause: One of the three motor phase windings has failed—an open circuit in the winding.
• Evidence: On Performance Line CX motors, this code sometimes occurs after a sudden stop from high torque (e.g., emergency braking on a steep descent). The winding can fracture at the connector.
• Fix: Motor replacement required. Do not ride with this code; the controller will continue to try to drive the failed phase, potentially overheating and damaging the controller board as well.

Code 502 – 2 Clicks

• Symptom: Motor stops intermittently, often after bumpy terrain or vibration.
• Cause: Loose or corroded motor cable connection at the controller or motor end.
• Fix: Unplug the motor cable, inspect for bent or green‑corroded pins, reseat firmly. Apply dielectric grease on the connector if corrosion is visible. This code is almost always a DIY fix.
• Stop point: If the connector looks melted or the pins are broken, stop—do not try to jumper the wires. Replace the cable assembly or drive unit.

Code 500 – 2 Clicks

• Symptom: Motor stops, display shows “Speed sensor” message.
• Cause: Speed sensor gap larger than 5 mm, or the spoke magnet is missing or misaligned.
• Evidence: The sensor relies on a magnetic field crossing a Hall‑effect switch. A gap over 5 mm or a magnet that has rotated out of position will cause intermittent cutouts—most common after a tire change or wheel removal.
• Fix: Adjust the sensor bracket so the magnet passes within 2–5 mm. Clean the sensor tip with a dry cloth. If the magnet is missing, buy a replacement (spoke‑mounted magnets are standard 10 mm diameter; verify thread size locally). After adjustment, test by spinning the wheel—the display should show a speed reading.
• Branch: If the magnet is present but the code persists, use a credit card to feel the gap. If it’s too wide, loosen the sensor bracket and slide it closer. If the gap is correct but the code won’t clear, replace the sensor itself (about $15–25, varies).

Code 603 – 2 Clicks

• Symptom: Error appears immediately after inserting a fully charged battery.
• Cause: Battery management system (BMS) fault—often a cell imbalance or a dead cell that the BMS cannot communicate with.
• Fix: Remove battery for 30 seconds, reinsert. If it still shows, fully charge the battery, then ride to about 20% capacity once. Still there? The battery needs replacement—cell imbalance of more than 0.3V between groups will trigger this code.
• Evidence: This code is common on batteries older than 3 years or after a deep discharge below 10%. A multimeter check across the battery terminals will show correct voltage, but the BMS internal voltage monitoring is what fails.

Other Error Codes Reference