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P1151

P1151 - Water separator alarm

Bosch · ECU Troubleshooting

What does P1151 mean?

This alarm signifies that the water separator has reached its capacity and needs to be drained. Water in the fuel can cause engine problems.

Common Causes

  • Water separator is full
  • Faulty water level sensor
  • Improperly drained water separator

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Drain the water separator according to the maintenance procedure.

  2. 2

    Check the water level sensor for proper function.

  3. 3

    Ensure the water separator is drained regularly.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

ECU internal faultECU internal fault - Electronic Control Unit internal errorP0008P0008 - No signal on both crankshaft and camshaft speed sensorP0122P0122 - Accelerator sensor 1 error (voltage low)
Source: Bosch ECU Troubleshooting
Open Manual (Page 7)Search more codes in this manual