ErrorBase

An error code? Check it before you pay.

The manufacturer's meaning, the checks in order and the evidence to ask for before you pay for a repair.

4COEVaillantF28E15P0171

1,542 entries verified against official sources

Medium risk4CWashing machinesSamsung washer 4C or 4E code: water not filling

Follow the technician while they repair

  1. Rules out the simple causes firstTechnician
  2. Measures the suspected partTechnician
  3. Shows you the measured valueTechnician
  4. Puts everything in writingTechnician

Repair justified

DaikinMicrosoft WindowsHTTPMicrosoft XboxBrotherCanonFroniusSMAAEGMiele

Choose your device

1,542 entries verified against official sources.

PlayStation 5 console with DualSense controller

Gaming and consoles

Console, accessory, game, account and network-service errors with evidence-led diagnosis.

Microsoft Xbox283 entries
Electric bicycle with mid-drive motor and integrated battery

Electric mobility

Bosch eBike Systems, Segway-Ninebot, Xiaomi

233 entries

Software and systems

Google Chrome, HTTP, Microsoft 365

202 entries
Air-to-water heat pump outdoor unit next to a house

Heat pumps

Daikin

199 entries
Front-loading washing machine

Appliances

AEG, Balay, Bosch

161 entries

Printers

122 entriesBrotherCanon

Solar and energy

86 entries

Phones and tablets

56 entries

Boilers

38 entries

Robot vacuums

35 entries

Laptops

31 entries

Vehicles

30 entries

HVAC

20 entries

EV charging

17 entries

Networks

14 entries

TVs

13 entries

Industrial machinery

2 entries
See all brands and categories

Most searched codes

Medium risk4CSamsung washer 4C or 4E code: water not filling
Medium riskOELG washer OE error code: drain problem
VaillantHigh riskF28Vaillant boiler F28: no valid flame was detected during ignition
High riskE15Bosch dishwasher E15: water protection activated
High riskP0171Ford P0171: system too lean on bank 1
High riskD80LG dryer d80 code: restricted exhaust airflow
HTTPLow risk500HTTP 500 Internal Server Error: an unexpected server condition blocked the request
High riskP0420Nissan P0420: catalyst efficiency below threshold

Don't pay for blind guesses

A code points to a system, not to a broken part. Every entry tells you what the technician must check and show you.

See how to control a repair

What was ruled out firstSimple causes are checked before the device is opened.

A measurement, not a guessThe measured value against the manufacturer's specification.

Everything in writingPart replaced, reference, reason and final test.