Junior Member, warming up (<31 posts)
Join Date: May 2019
Location: Liverpool - UK
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e39 - 145 Lambda Regulator 2
My first post on this forum - wish it was an introduction thread, instead - I'm asking for help already!
Purchased my 2001 M5 two months ago, it was a dream purchase for me, having had a few e39s prior to this (530d).
The model I bought was from the lower end of the market, given it had a few items needing attention - the first of which being a paddle clutch which needed removing.
My aim is to put right any issues the car has from a mechanical aspect first, then move on to the areas of bodywork that need attention.
On the whole, its a good car, few small issues - nothing serious. I however am impatient, so the past two months have been fairly expensive in terms of parts (I did budget a little extra for immediate repairs).
I have covered around 1500 miles in the car so far, all of which have been trouble free - apart from realising the engine hasn't been running at its full potential.
I changed over the spark plugs yesterday and plugged into INPA - there was a code for 145 - Lambda Regulator 2, I cleared this and it came back immediately - this is the issue I am having at the moment.
After a quick search, most people seem to point the finger at defective MAF sensors, I unplugged them to see how the car performed under the alpha-n condition and it blew me away, the car had never felt so powerful since I bought it.
My initial thoughts were to purchase replacement MAFs, however I feel it may be a false positive and another issue causing the code. Thankfully Jamie lives locally and has a spare set - so aiming to test these over the next few days.
A few things I have tried so far;
- Switched the MAF sensors - no difference.
- Switched the pre-cat lambda sensors - no difference, same 145 code.
What I did notice when I removed the MAFs was that the seal from the bank 2 MAF to the intake pipe was missing but still appeared to be sealed, I switched the seal from bank 1 but still got the same 145 code after clearing (I will order a replacement anyway).
I had the exhaust removed whilst changing the clutch the other month, I replaced the firing rings / gaskets from the downpipe - which appear to be sealed properly.
My plan for tomorrow is to remove the intake plenum to see if there are any splits on the intake gaskets or vac lines, hope I'm not leading myself down the wrong track if it turns out to be the MAFs, but no harm in checking anyway.
Will report back with my findings, but wondered if anyone else has experience with the same code / problem?