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Self-diagnosis
Readout specifications for boost pressure control
Display group 11 at full throttle (test drive in 3rd or 4th gear, coolant temperature not below +85 °C)
- engine codes AGR and ALH
Important The fault reader must be secured on the rear seat and operated from this position. Observe the safety precautions applicable to test drives .
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Read measured value block 11
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◂ Indicated on display
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3340 rpm
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1830 mbar
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1850 mbar
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68 %
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Duty cycle (actuation) of boost pressure limitation solenoid valve -N75
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Current boost pressure
▪ If as specified in display zone 2 (tolerance ±100 mbar) OK.
▪ Boost pressure too low: no boost pressure control => check
▪ Boost pressure too high: solenoid valve -N75 jamming
▪ Pressure hose for boost pressure control detached or blocked
▪ Booster linkage rusted solid, vacuum unit defective
▪ => check boost pressure
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Boost pressure specified by control unit
▪ 1800...2050 mbar OK
▪ > 2050 mbar: boost pressure increased as a result of tuning
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Engine speed, 2900...4000 rpm OK
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Display group 11 at full throttle (test drive in 3rd or 4th gear, coolant temperature not below +85 °C)
- Engine codes AHF and ASV
Important The fault reader must be secured on the rear seat and operated from this position. Observe the safety precautions applicable to test drives => Page 23-1.
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Read measured value block 11
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◂ Indicated on display
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3340 rpm
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1948 mbar
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1917 mbar
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57 %
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Duty cycle (actuation) of boost pressure limitation solenoid valve N75
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Current boost pressure
▪ If as specified in display zone 2 (tolerance ±100 mbar) OK.
▪ Boost pressure too low: Check boost pressure control
▪ Boost pressure too high: solenoid valve -N75 jamming
▪ Pressure hose for boost pressure control detached or blocked
▪ Booster linkage rusted solid, vacuum unit defective
▪ Check boost pressure
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Boost pressure specified by control unit
▪ 1800...2250 mbar OK
▪ Over 2250 mbar: boost pressure increased as a result of tuning
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Engine speed, 2900...4000 rpm OK
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