Bosch error 0x550358: Short circuit in the rear light circuit
The drive unit has detected a short circuit on the rear light circuit. The system typically disables the rear light and may switch motor support off or into a limp mode until the fault is cleared. The bike will still pedal normally, but lighting-dependent features and full assist behaviour are compromised.
| Drive system | Bosch eBike (DiagnosticTool / eBike Flow hex code) |
| Severity | Fix at home |
| Keep riding? | Safe to keep riding |
| Typical cost | Rear light replacement typically runs 20 to 60 EUR for the Bosch unit plus 30 to 60 EUR labour; full harness repair or drive unit diagnostics at a dealer usually lands between 80 and 180 EUR. |
Likely causes
- Damaged or pinched cable in the rear light wiring, often where it passes through the rack or mudguard.
- Water ingress into the rear light housing or connector after heavy rain or washing.
- Corroded or loose contact in the rear light plug at the rack or frame.
- Failed rear light LED module with internal short.
- Aftermarket rear light fitted without a compatible suppressor or wrong wattage.
- Trapped cable between rack struts or seat tube clamp.
- Crushed cable where the rack mounts to the dropouts.
How to fix Bosch error 0x550358
- Switch off the system and remove the battery before inspecting any wiring.
- Unplug the rear light connector at the rack and inspect both sides for green corrosion, bent pins or moisture.
- Trace the rear light cable along the rack and look for chafing, pinch points or crushed sections, especially near rack mounting bolts.
- Refit the original rear light if an aftermarket unit was installed, as Bosch lamps include the required suppressor.
- Clean and dry the connector, apply a small amount of dielectric grease, reconnect firmly and refit the battery.
- Power the system on and check whether the error clears; if it returns, leave the rear light disconnected and ride with front light only until the cable is replaced.
- Take the bike to a Bosch dealer for cable or rear light replacement if the fault persists, as the drive unit output stage may need inspection.
Warranty: A genuine rear light or wiring loom fault inside the two-year warranty period is normally covered, but water ingress, crash damage, aftermarket lamp fittings and rodent-damaged cables are treated as wear or misuse and excluded.
Typical cost: Rear light replacement typically runs 20 to 60 EUR for the Bosch unit plus 30 to 60 EUR labour; full harness repair or drive unit diagnostics at a dealer usually lands between 80 and 180 EUR.
Frequently asked
Can I reset bosch error 0x550358?
A power cycle (battery out, wait 30 seconds, refit and switch on) sometimes clears a transient short. If the rear light cable is still shorted the code will return as soon as the light is powered again, so the fault must be physically repaired first.
Is it safe to keep riding with this error?
Yes, the bike will pedal and assist, but the rear light will usually be off, which makes riding in low light or at night illegal and unsafe. Ride with a separate rear light and get the fault fixed before the next dark commute.
How much will the repair cost and is it under warranty?
Expect 20 to 60 EUR for a replacement Bosch rear light and 40 to 100 EUR fitted at a shop, more if the harness needs replacing. If the bike is under two years old and the loom has not been damaged by water or impact, Bosch normally covers it as a warranty repair.
Related Bosch codes
Manuals and video
- Bosch eBike Help Center: official error-code index
- Bosch eBike downloads: quick start guides and battery guide
- Bosch eBike dealer search (DiagnosticTool readout)
Official source: www.ridewill.com
Not an official Bosch document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.