Hi - My car has developed a fault of the dreaded limp mode, had it put on diagnostics and it reads 17965 - P1557 - Charge pressure control Regulating limit surpassed. I've had the MAF replaced, and the top Turbo Intercooler pipe replaced, but still get this fault. Limp mode only really happens when i exceed 3500 rpm, sooner if driving on a hill. Don't think it's the turbo, as I have been driving with this fault since early this year, and the fault has not gone any worser/better. Any ideas?