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Audi 1.8L Turbo engine, 225hp model. The car had no CEL on but the flex pipe in the front exhaust pipe was broken. I replaced the pipe, but then on the first drive got a CEL with the P0130 code. I figured I bent the wire on the pre-cat O2 sensor too much, so I replaced that with a new one. Still the error came back. I borrowed a friend's OBDII scanner to get a better insight.
It seems to enter CL well, and is OK at idle and mild engine rpm changes. But it seems like when I stab the throttle and snap the throttle shut, it enter OL-Drive during RPM down, and then OL-Fault. I notice the EQ_RAT and O2S readings, which normally look OK, are pegged at about 1.999 and 3.2222 during this period and then the OL-Fault is triggered. I thought these readings indicated an out-of-range value that was triggering the fault, but my understanding now is that during this period the ECU is shutting off the fuel? So these lean readings would be OK?
I also checked the short term fuel trim and it seems to be around -7%, which seems reasonable. I'm out of good ideas and will soon revert to randomly replacing parts, which I hate doing. Is there any insights someone might have on this? Anyway to determine exactly what value the ECU doesn't like?
Hi
Have you found the answer?
I have T4 caravelle from 2001 with same fault code. Its set when lambda sensor heater voltage gets below 10.5V. Its the ground wire from the ECU.
Before realising that this fault was present when the lad bought the van with the cell illuminated and seller told him to get rid of by lifting the battery terminal, I changed the lambda.
I was about to change the ECU - but its hard to find for this petrol, 2.5i engine.
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