Hello gents. 2006 with 232,000 miles on it. Love the thing to death but the check engine light has been on for about nine months. Since she’s old I don’t like spending a ton of money on her so I’ve been Tinkering around with her myself. I had concluded that she needed a MAF sensor which I installed. No dice. The check engine light appeared immediately. Fast forward, I have an Expired inspection and so I was forced to take it to my local mechanic to see if he could figure it out. He is not a rover mechanic by any stretch of the imagination but he’s a very good honest guy who swears by his own diagnostic prowess. Calls me next day and basically tells me that the car needs a MAF sensor. He said the one I installed wasn’t OEM and it’s causing the issue. Done. $500 later, I pick the car up and she’s driving just fine. I drive about 25 miles and under previous conditions the check engine light would have already reappeared. I felt pretty confident that the issue was fixed until the check engine light came back on. I just plugged in my tool and to my surprise the freeze-frame data says that I actually now have a Rich Code!

I then proceed into the Landrover diagnostics Part of my scan tool and it actually has two Rich Codes and two lean Codes. What’s happening? Is the car’s computer just trying to figure **** out right now?

what’s my step? Keep driving her for a few cycles ?

 

If the MAF is/was bad you do usually get a MAF code. Rich/lean codes are generally O2 sensor codes. When were the upstream O2 sensors last changed? Dont forget that when replacing critical parts, like the MAF, you must do a hard rest after to clear adaptations.

And as for the MAF, you do not need an OEM MAF. Actually OEM is Denso anyway. You do need the correct MAF though. Also check your intake tubes for cracks, particularly near/after the MAF. Seems the plastics like to crack around the worm clamps.

 

I had an intermittent MIL light which I traced back to the rear O2 sensors that needed cleaning, were sooty. Cleaned with brake cleaner and an air line. Not hard to get out either, make sure connectors go back fully.

 

Downstream O2 sensors are only for verifying cat integrity. They will not generate lean/rich codes and have no impact on economy, etc.

 

That is correct, but they will turn the MIL light on

 

Right, but that is not what this thread is about.

 

I do realise the OP refered to MAF - but, as shown in his text.

But we all learn from what individuals say

 

Throttle body adaptation

 

I guess I am just not quite getting your thoughts on why you think a downstream O2 sensor could cause rich/lean codes but not throw a catalyst efficiency code. Maybe you can better explain?

 

Can you explain “hard rest” ? I couldn’t help myself today and cleared the codes. Back on and we are now back to lean codes on both banks - which was the original situation. So - I have an new MAF sensor and the same problem. The sensor is a delhi - not denso ... for what it’s worth.

I need to check records on the 02 sensors but they were replaced. There WAS and issue w one of them however. I’ll circle back.

UPDATE. Invoice from 02 sensors attached.
what puzzles me is that he returned the vehicle without a check engine light and inspected me - the light didn’t come on for quite a bit of time - which is why I didn’t connect this issue to what’s noted on this invoice.

In advance - could someone explain what would be entailed to fix the “broken “ o2 sensor ?


https://imgur.com/gallery/iMajWbN