AFT_B009

SEPTEMBER 2020 AFTERMARKET 25 www.aftermarketonline.net measuring the new sensor, the signal voltage KOEO was 1.07 volts. As a quick check, I plugged in the old sensor and it read 1.64v so 0.5 volts difference. Bear in mind, for this sensor, this will make a massive difference in pressure conversion by the ECU. Checking live data, I now had my 1 bar pressure I was looking for so the new sensor appeared to be faulty as the voltage for static engine off pressure was too low and the ECU was looking for 1.6v. Starting the engine, the boost pressure barely rose, so I had fixed one fault but we still had another issue and more than likely the initial complaint. Noting faults and clearing them only left p0045 boost pressure valve low voltage. Remember from before when I had no change in position from the control actuator? Well, now I had change, but it was very slight and far less than I expected to see. Turbo and actuator movement So where to next? I decided to visually inspect the turbo and its actuator movement with someone increasing engine speed to see what happened. Upon inspection, I found the actuator arm was remaining still but showing signs the actuator was attempting to move, but wasn’t able to. I then decided to check movement of the linkage arm that the actuator moves. On some turbo assemblies, this can be done fully assembled or activated via a scan tool special function, but on this unit the motor was locked and attempting activation didn’t work, possibly due to there being a stored fault code. This meant the linkage had to be removed from the actuator, Upon removal, the linkage arm and pivot were tight and it took considerable force to move through its full travel so we had found the cause of the fault. The low voltage fault was being logged as the position of the arm wasn’t where the ECU was commanding it to be, and as it stayed where it was (low) a corresponding fault code was set. After cleaning and lubricating the arm and pivot I managed to get everything free and greased up to prevent a reoccurrence. Once reassembled, I then checked MAP pressure in live data now seen a nice increase in pressure in line with engine speed and could now hear an audible whistle from the turbo indicating it was creating pressure. A long road test monitoring data confirmed correct operation and the vehicle was returned to its owner. Understanding This article highlights the importance of understanding what a fault code is telling you, and also why it pays to spend time learning to understand to make an accurate diagnosis. Like everyone, I don’t know the meaning of all fault codes and this is where technical data comes in and plays an important part in diagnosing faults. As for the faulty new map sensor? Well, after some digging it was actually the wrong sensor supplied, even though it fit and plugged in. It was actually for the 2.2 engine which uses a different intake/turbo layout.