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P238A Powertrain

Water in Fuel Sensor B Circuit

A general circuit fault on the secondary water-in-fuel sensor B - typically used on diesel systems with two filter housings (pre-pump and post-pump). The ECU loses water-detection feedback on this stage; risk of water reaching the high-pressure pump and injectors.

Affected components

  • Water in fuel sensor b
  • Fuel filter housing b

Common causes

  • High likelihood: Open in sensor or wiring

Diagnostic notes

  • The malfunction indicator lamp may illuminate

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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