SPN 4354 — DEF/urea fluid level — low

Likely causes

• Empty DEF tank or level sensor reading low
• Faulty or frozen DEF level sensor in winter
• Leak at the tank, lines, or DEF dosing unit

Recommended checks

1. 1

   Fill the tank with ISO 22241-certified DEF

2. 2

   Check the level sensor and tank heater in winter

3. 3

   Inspect the DEF system for visible leaks

Parts to replace

• Certified DEF fluid

  AmazonRockAuto

• DEF level sensor

  AmazonRockAuto

• DEF dosing unit

  AmazonRockAuto