Get your trusted passenger again and go for a drive. As the boost builds, the meter should show about 12-14V as the turbo boost gauge reaches the yellow section. If the gauge continues to rise into the red section but the meter shows positive voltage to the AMAL valve the fault is restricted to the mechanical side of the control. If no voltage is shown the fault is electrical and you should have the wiring, fuses and MABC or EMC systems checked by someone with suitable qualifications. Hit the button to contribute a TechTip.
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