D5254T (to 2002, Audi) - 2000 V70 2.5D MAF Problems

Richard_TD · Mar 29th, 2015, 18:18

Our recently acquired V70 TDi isn't boosting properly, and wasn't when we got it. It's a late model with the MSA 15.8 system. I thought the waste gate being held on with jubilee clips and wire might have been the root cause but there was no change when I fitted another turbo.

A VIDA-DICE scan showed two codes, before and after the new turbo was fitted- ECM-000B Mass air flow (MAF) sensor - Signal too low and ECM-001D Turbocharger (TC) control valve - Signal too low. I believe a previous owner fitted a new MAF sensor, so I'm ruling that out for the moment.

I've checked the voltages at the MAF plug and got

1. +5.02V
2. close to 0V
3. 0V
4. +5.01V
5. 0V

Some Googling suggests that Pin 2 should have +12V. Is that correct, and if it is where should I be looking? The wire just disappears into a harness but I don't know where it goes. Is there a fuse anywhere? Would it be ok to connect it to another 12V supply?

For the moment I'm not looking at the TC Control valve, I've a feeling it will start getting the right signals once the MAF is working.

Mar 29th, 2015, 18:18	#1
Richard_TD Master Member Last Online: Mar 13th, 2020 17:15 Join Date: Mar 2009 Location: Fife	2000 V70 2.5D MAF Problems Our recently acquired V70 TDi isn't boosting properly, and wasn't when we got it. It's a late model with the MSA 15.8 system. I thought the waste gate being held on with jubilee clips and wire might have been the root cause but there was no change when I fitted another turbo. A VIDA-DICE scan showed two codes, before and after the new turbo was fitted- ECM-000B Mass air flow (MAF) sensor - Signal too low and ECM-001D Turbocharger (TC) control valve - Signal too low. I believe a previous owner fitted a new MAF sensor, so I'm ruling that out for the moment. I've checked the voltages at the MAF plug and got 1. +5.02V 2. close to 0V 3. 0V 4. +5.01V 5. 0V Some Googling suggests that Pin 2 should have +12V. Is that correct, and if it is where should I be looking? The wire just disappears into a harness but I don't know where it goes. Is there a fuse anywhere? Would it be ok to connect it to another 12V supply? For the moment I'm not looking at the TC Control valve, I've a feeling it will start getting the right signals once the MAF is working.

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