iRobot robot vacuum Charging Error 21 error
ErrorCharging Error 21
Charging Error 21 is identified by iRobot support as the robot is docked but cannot maintain charging. Follow the model-scoped external checks and service boundary below.
What the code means
The robot is docked but cannot maintain charging
Follow the exact model manual. Clean the robot and dock charging contacts, secure the dock power cable, and contact iRobot if the robot still loses charge while docked. Do not open fixed panels or test live circuits.
Typical symptoms
01Charging Error 21 appears on the robot vacuum display or app
02The appliance stops, pauses, or refuses to complete the affected function
03The code returns when the same condition is present again
Likely causes
Start with the least invasive explanation and stop if the check requires internal electrical or sealed-system access.
01The robot is docked but cannot maintain charging
02A model-specific condition must be confirmed against the exact manufacturer instructions
Safe next steps
- 1Clean the robot and dock charging contacts, secure the dock power cable, and contact iRobot if the robot still loses charge while docked.
- 2Do not infer or order an internal component from the code alone.
Step-by-step diagnosis
- 1Record the complete Charging Error 21 message and the full iRobot robot vacuum model
- 2Confirm that the displayed code matches the official source entry
- 3Complete only the external checks described by the manufacturer
- 4Run one controlled test and stop if Charging Error 21 returns
Step-by-step repair
- 1Clean the robot and dock charging contacts, secure the dock power cable, and contact iRobot if the robot still loses charge while docked.
- 2Do not infer or order an internal component from the code alone.
Repair details
€Estimated cost
The published checks normally need no part. A confirmed battery or dock repair is model-specific; obtain an iRobot-compatible quote before purchase.
The published checks normally need no part. A confirmed battery or dock repair is model-specific; obtain an iRobot-compatible quote before purchase.
⏱Estimated time
About 10–20 minutes for the published contact, dock, temperature, or battery checks; replacement time depends on the exact model.
About 10–20 minutes for the published contact, dock, temperature, or battery checks; replacement time depends on the exact model.
🔧Tools
Soft dry cloth for charging contacts, Exact-model battery instructions, No electrical test tool
Soft dry cloth for charging contacts, Exact-model battery instructions, No electrical test tool
▣Spare parts
Use only an authentic iRobot battery if the official diagnosis confirms replacement; Charging Error 21 alone does not identify a battery part.
Use only an authentic iRobot battery if the official diagnosis confirms replacement; Charging Error 21 alone does not identify a battery part.
What not to do
- Do not use sharp tools, force covers or contacts, or repeat tests if Charging Error 21 returns.
Preventive maintenance
- 1Keep the robot and dock contacts clean and dry, use the official battery for the model, and retain the exact-model support instructions.
Frequently asked questions
What does Charging Error 21 mean?
iRobot describes it as the robot is docked but cannot maintain charging.
Can I replace a part from the code alone?
No. Confirm the exact model and manufacturer diagnosis first.
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