Lexus IS250 Knock Sensors (55 Plate) - Any info appreciated
10-04-16, 06:25 AM
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Lexus IS250 Knock Sensors (55 Plate) - Any info appreciated
Hi all,
I'm new here - first time Lexus owner, a friend of mine was selling his car as his work van died and he needed to raise funds quickly so it worked out well for both of us.
What I got was a very well looked after Lexus IS250 55plate - so it's 2005 technically but I believe is the 2nd gen model - going by photos for sure anyway.
When he passed me over the car he included two knock sensors and said that they needed to be replaced as he was getting a Check Engine Light and the codes came back to say there was an issue with the knock sensors - also the car lost quite a bit on the MPG which I am led to believe could be faulty knock sensor related? roughly 8mpg I think he said.
A good friend of mine is a Mechanic and he is looking into doing the job for me but I just wanted to get some second opinions/advice and obviously this would be a good place to start;
I did check these forums and found varying info but hoping someone could shine some light on the above.
Hopefully once this is sorted my posts on here will be upgrade and improvement related and not technical issues!
Cheers!
I'm new here - first time Lexus owner, a friend of mine was selling his car as his work van died and he needed to raise funds quickly so it worked out well for both of us.
What I got was a very well looked after Lexus IS250 55plate - so it's 2005 technically but I believe is the 2nd gen model - going by photos for sure anyway.
When he passed me over the car he included two knock sensors and said that they needed to be replaced as he was getting a Check Engine Light and the codes came back to say there was an issue with the knock sensors - also the car lost quite a bit on the MPG which I am led to believe could be faulty knock sensor related? roughly 8mpg I think he said.
A good friend of mine is a Mechanic and he is looking into doing the job for me but I just wanted to get some second opinions/advice and obviously this would be a good place to start;
- Should I change the wiring harness as well - just to make sure it isn't a wiring problem and not a Knock Sensor one?
- How difficult is this job - my friend has told me its about 2 and a half hours but he is unsure yet as to what he will need to take out to access the knock sensors as he is waiting to hear back from Lexus - maybe someone here could shed some light?
I did check these forums and found varying info but hoping someone could shine some light on the above.
Hopefully once this is sorted my posts on here will be upgrade and improvement related and not technical issues!
Cheers!
10-04-16, 10:54 AM
#2
Racer
Welcome to Lexus! I don't view bad oxygen sensors as a serious problem mechanically. There are upstream knock sensors located before the catalytic converters and downstream sensors located after the catalytic converters. A bad downstream sensor is not very detrimental to the car. The check engine light tends to annoy the driver more than anything else. However, the upstream sensor does affect the car's performance. It can cause the engine fuel mixture to run rich, lowering the gas mileage, which seems to be the situation you have.
I would not replace the wire harnesses for the O2 sensors, this is rarely needed. Wire does not go bad. Check to see if it is broken. If not leave it alone. Go ahead and drive the car all you want. You won't hurt the car.
I would not replace the wire harnesses for the O2 sensors, this is rarely needed. Wire does not go bad. Check to see if it is broken. If not leave it alone. Go ahead and drive the car all you want. You won't hurt the car.
10-06-16, 01:55 AM
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Welcome to Lexus! I don't view bad oxygen sensors as a serious problem mechanically. There are upstream knock sensors located before the catalytic converters and downstream sensors located after the catalytic converters. A bad downstream sensor is not very detrimental to the car. The check engine light tends to annoy the driver more than anything else. However, the upstream sensor does affect the car's performance. It can cause the engine fuel mixture to run rich, lowering the gas mileage, which seems to be the situation you have.
I would not replace the wire harnesses for the O2 sensors, this is rarely needed. Wire does not go bad. Check to see if it is broken. If not leave it alone. Go ahead and drive the car all you want. You won't hurt the car.
I would not replace the wire harnesses for the O2 sensors, this is rarely needed. Wire does not go bad. Check to see if it is broken. If not leave it alone. Go ahead and drive the car all you want. You won't hurt the car.
Hi Dennis, thanks for the welcome!
I think you may have mixed up the Knock Sensors with the Nox Sensors?
Either way me and my friend got started on this last night - took the intake manifold out and there is two Knock Sensors under it one for each bank. Changing them around tonight and hopefully that will have fixed the issue - might leave this post up just incase anyone encounters the same issue.
A garage quoted me a ridiculous amount of money for what was basically unscrewing some bolts and a bit of general knowledge of mechanics - took about an hour and a half in total and anyone with a friend who is in any way car inclined could do it quite competently.
Ste
10-07-16, 03:51 AM
#4
Racer
But I'm glad to see that you got the problem solved..
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