Hi everyone.
Well here’s my problem. I have totally serviced my 2.1 petrol 2003 including replacing all four lambda sensors. Upon completion I made sure all the vacuum hoses were tight and no leaks and yet......I’m still getting the MIL light up and the code of P1646/7, it’s driving me nuts not knowing what the problem is, even though the engine is running very smooth has great acceleration.
please can anyone help solve the mystery.

thanks in advance

Hayden

 

Not sure how it is in a 2.1 as the sheet I have is for the 2.5 and 3.0,, but after you replaced the oxygen sensors did you erase the codes or it was just after the repair the check engine light is still on? If it is the latter, you probably haven't reached the proper amount of drive cycles yet. If the condition has, in fact, been fixed, then the light will go out on its own after a while if the condition doesn't show itself.

 

Hi yes cleared all codes on completion, then took it on a run for 12 miles then the MIL came back on and the code P1646/7 came up on my isoft unit. With this code which sensor does it indicate the faulty one is?

 

46 & 47 are bank 1 & 2, #1 sensors (upstream), the gray plug ones. First did you buy OEM sensors? There are dozens of posts about people buying lesser expensive (usually internet saying they are OEM, but don't function correctly). Check your fuses first.

 

Those codes are for the upstream sensors on both banks. It is saying they both have issues. , by list is for the 2.5 and 3.0 liter engibes. Would guess they would be teh same for the 2.1 liter too, but not sure. Maybe a Euro member can chime in. We never got the 2.1 liter here in the States.

HoweverThere are no other codes? Hard to believe both of them would go on their own at the same time.

 

As those are the "heater element" ones, do check the fuses, the wiring (harness), the connections (clean the contacts). Check to see you have power to the green/white wire.
One report of a split breather pipe causing both codes to be thrown.
Also check the induction hose on the fuel rail = part #C2S28870.
Curious as to what prompted you to replace all 4 in the first place?

 

Thanks to you both. I think you have both hit the mail on the head...OEM sensors! I have checked all the fuses, all good, and cleaned all the connections. I chose to change all the lambda sensors as the car had already done over 125k miles and the guy who I bought it from never really looked after it, I bought it as a project car with a view to slowly rebuild and get her back on the road and I have to say so far so good.
so my question is, is it best to buy the Bosch lambda sensors or are there others you would recommend?

thanks once again for your help and support

 

I would get the OEM ones as you occasionally hear stories where cheaper ones have issues. Can't say for certain if that is true or not, but for the little more cost for the sensors versus the amount of work involved changing them more than once, seems like money well spent. Up to you.

 

As I mentioned, there are numerous posts of people using purported OEM (usually internet cheaper buys) & being frustrated with them not working correctly. A couple of people even resisted my suggestion and replaced them more than once with the same results. When they bought the proper ones, all was well.

I suggest looking at SNG Barrett (a forum sponser) as well as Rock Auto, Parts Geeks, AutohausAZ, Jagbits for quality parts. Bosch, Denso are both good ones.

 

OE are maybe Denso.

Be sure to check what you have are the right kind and yes check fuses/relays/wiring.

 

Jagbits sells the correct sensors for your X-type and we give all forum members a 10% off coupon code:
https://www.jagbits.com/ssearch.html...+sensor+x+type

 

Once again guys a big thanks from across the pond I will be hot on the trail of two good lambda sensors and once I’ve fitted them I will let you all know the outcome. By the way I would buy from jagbits but we get hit with import taxes but thanks for the offer.
brilliant and thanks for now.

Hayden

 

Hey guys, well I bought two Denso lambda sensors and fitted them within four hours, minus the coffee breaks. Deleted the codes then took it for a twenty mile round trip and the MIL didn’t come back on again, so problem solved.
A big thank you to all you guys who helped me solve the problem, couldn’t have done it without you all.
thanks from across the pond
Hayden

 

It's a pain there are mix ups because of internet (cheap) buys that cause so many problems.

 

Hi, yes it is but once you learn of the mistake you quickly learn the lesson especially with all the time and effort that goes in to changing these sensors, thank goodness for knowledgeable people like yourself and others on this forum.