S-Type 2.7D Odd Problem

mrmike · March 3, 2022

Hi Guys something maybe a little different, I know zero about diesels and the noises they make, They always seem to be like petrol engines about to give up the ghost. Anyway have a read and let me know what you think.

Nearly a year ago I replaced the A/C compressor and everything seemed to be OK. No DTCs except for the odd Headlight levelling one soon to be sorted.

Some time ago after the above job I noticed that the top Hose connecting to the Airbox was loose. I pushed it up and tightened it but I came loose quickly and I repeated the operation quite a few times, most of the time it was loose. During all this no DTCs even after several long trips of 3K Kms. Last week I found why the Hose was coming loose and tightened it properly. After noticing the missing Head Lamp dance, I checked the OBD DTCs, wow on top of the HL I got:-

P140A Exhaust gas recirculation sensor C circuit low.

P010C Mass or volume air flow B circuit Low.

P010F Mass or volume air flow sensor A/B correlation.

Before this I had had a little thrash on the motorway using good acceleration, much better than when the hose was loose, Always No smoke.

I reset the DTCs and drove around locally for a couple of days and then checked again

This time I got the P140A and P010C DTCs again.

I am inclined to loosen the Hose again and see if it goes back to normal.

Looking at airflow readings it looks OK. I have no lights or RP.

Perhaps I just need to diss the battery and do a reset.

BTW Turbo lag is quite noticeable on pulling away, I was thinking of blocking the EGRs at the MAP/butterfly inserting a simple plate without removing the hoses going to the EGRs. This is an easy test to do without any access probs.

One doubt I did have when Remounting after the compressor change was whether I had not mixed up the MAF cables as it was possible!!

mrmike · March 14, 2022

Disconnected the battery and did about 80Kms, Now I get just theP140A Exhaust gas recirculation sensor C circuit low. Accelerates really well, with no smoke of any sort, actually starts immediately and is much smoother. Averages 9L/100kms. Got crap weather here, storms all this week. But if I can put off painting orders from her indoors I might just make some Ally EGR blanking plates and gaskets for a test next week.