20E2

Boost pressure too high


Possible cause:

- Charge pressure control
Affected functions:

- Engine output

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Test 1: Check system 'Charge pressure control'.

1. Check system 'Charge pressure control'.
Figure legend/figure

- 019 -Overpressure-Vacuum tester
- a -Hose connection to component Y31/5 (Charge pressure control vacuum transducer)
- b -Hose to component 'Y31/5 (Charge pressure control vacuum transducer)'
Test sequence

- Switch off ignition.
- Remove components Covering at engine and Lower engine compartment paneling.
- Detach hose a to component Y31/5 (Charge pressure control vacuum transducer) at component 'Charge air cooler, right cylinder bank' and connect pressure/vacuum tester to hose b.
- Apply pressure to the vacuum cells for the boost pressure control valve with a pressure of approx. 800 mbar set on the pressure tester.
Specified value

- With the system leaktight, the pressure may drop by no more than 50 mbar over 1 min.
Question

- Is the pressure maintained?







YES
Figure legend/figure

- 110bRight turbocharger
- 110/3bControl rod
Test sequence

- Check whether control rod (110/3b) from the vacuum cell to the boost pressure control valve (left and right cylinder bank) is extended by 8 - 13 mm.
Question

- Is the test o.k?







YES
Test sequence

- Use pressure tester to adjust pressure to approx. 800 mbar.
- Switch on ignition.
- Briefly actuate component Y31/5 (Charge pressure control vacuum transducer).
- Bridge between sockets (3.4) 37 and (2.23) 32 of the 126-pole socket box tester.
Specified value

- Overpressure< 400 mbar
Question

- Is the pressure achieved?







YES
The test is o.k..End of test

NO
The test is not o.k..Possible cause and remedy

- Y31/5 (Charge pressure control vacuum transducer)
- Left or right vacuum cell
End of test

NO
The test is not o.k..Possible cause and remedy

- Control rod is bent
- Boost pressure control valve is stuck (stays closed).
- Hose from component Left or right vacuum cell to component Y31/5 (Charge pressure control vacuum transducer) is pinched
End of test

NO
The test is not o.k..Possible cause and remedy

- Hose to component 'Y31/5 (Charge pressure control vacuum transducer)'
- Hose from component Left or right vacuum cell to component Y31/5 (Charge pressure control vacuum transducer)
- Left or right vacuum cell
- Y31/5 (Charge pressure control vacuum transducer)
End of test