Powertrain, generic (extended)

P226A Water in Fuel Lamp Control Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P226A concerns the output that switches the water-in-fuel warning lamp, not the sensor. The control unit drives the lamp circuit and checks it electrically; an open lamp, a broken wire or a shorted driver lets it set this code. No manufacturer documents P226A publicly, and on current vehicles the cluster usually receives the warning as a bus message, so a discrete lamp line that could fail is found mainly on older or commercial diesels. The practical risk is that the driver is no longer warned when the separator fills, while the sensor itself keeps working and P2269 can still be stored. CARB treats the warning lamp as part of the driver information, not as an emission input, so this code normally does not turn on the MIL. Check bulb, socket, wiring and driver output.

Likely causes

Burnt-out warning lamp or corroded lamp socket
Open or shorted wire between control unit and lamp
Faulty lamp driver in the control unit

Symptoms

  • Water-in-fuel lamp does not light during the bulb check at ignition on
  • Lamp stays on permanently regardless of the filter state

Repair estimate

DifficultyEasyDIY possible
Parts and labour€10–250
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

water in fuel indicator

Related codes

P2269P2264

References: law.cornell.edu, en.wikipedia.org, patents.google.com.