VW Passat 1.9 TDi 2002 - Loss of Turbo power, codes P1556 & P1144 - Fixed #
Posted by Ian Waring on February 5, 2015, 11:14 pm
Year of Manufacture *: 2002 Engine Size and Code *: 1.9 Tdi
Vehicle is flat at Low Revs but plenty of Revs at Top End.
Have not removed Exhaust, but am sure Exhaust is not blocked as there is plenty of power above 2000 Revs.
2 Codes:
P1556 Charge Pressure Control negative deviation.
P1144 Mass Or Volume Air Flow Circuit Open Short to Ground.
Have carried out Smoke check and no faults found.
Maf Sensor Signal Wire has been grounded to earth.
Have tested Turbo Control Valve on Engine Start Up and Actuator Rod moves fully. Have carried out same test with Vacuum Gauge and it moves freely.
I am now looking at the Turbo Boost Control Solenoid which is the N75. Am I correct in saying: if this Valve goes faulty, it switches the Maf Signal Wire to earth, as in Limp Mode, to stop High Turbo boost?
As I write, I have just thought of another test for Maf .. Maf Sensor Code will delete with just Ignition On, but when Engine started, code reappears.
Will delete Maf code and see if Signal Wire has a 1 volt reading rather than being earthed.
Chris???!! Scratching my head - where did that come from!
Thanks Mark! (and Kevin for pointing out my error
Realised that it was a Maf Sensor fault because after testing wiring Maf Sensor, had 12v supply, 5v reference supply, good earth but no output voltage.
Never tested a Maf where there has been no output voltage whatsoever. Another lesson learned.
on February 5, 2015, 11:39 pm, in reply to "