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[Garryw330]

Hi everyone, hopefully someone can help. I have a 2009 B6 2.0tdi estate with 149k on the clock, does approx 2000 miles a month. The issue I have is intermittently when switching on the ignition only (no cranking) I get a engine fault with the following codes logged. P0193 fuel rail sensor A, P0122 throttle pedal sensor A, P0405 EGR sensor A and P2564 turbo boost sensor A. If try and start it either just cranks or may start eventually but I’m limp mode. Any ideas or should it be scrapped??

[Crasher]

Scrapped! It's only 11 years old; even if it is fuel of the Devil... Which engine type code, CBAB? These codes are all interlinked

000290 (P0122) - Throttle Position Sensor (G69): Signal too Low
16577 (P0193) - Fuel Rail Pressure Sensor (G247): Circuit High Input
04900 (P0405) - EGR Sensor 1 (G212): Signal too Low
18996 (P2564) - Turbocharger Boost Control Position Sensor (G581): Signal too Low

All four sensors are on the same power supply and earth circuit plus the crank speed sender G28 is also connected but is not an OBDII code so your generic reader won’t pick it up. Interestingly the fuel temp sender shares the earth (which is supplied direct from the ECU) so you would think the earth circuit is intact or it would come up as a fault so that leads me to suspect the 5 volt power output from the ECU at pin 25 of the 60 pin smaller plug (as a yellow/blue) has a problem, either with the 5v output of the ECU itself of more likely the connection point buried somewhere in the engine harness (usually a few inches back from the ECU) has a corrosion issue but I have also seen water in the EGR valve pot spike the system and cause running problems.

[Garryw330]

Thanks for the guidance. Have removed the ECU and checked the connections. Found the yellow/blue wire pulled. Repositioned and made sure pin was secure. Fault cleared and not returned for 30 ignition cycles so fingers crossed. Thanks again