p0171 keeps coming back even after replacing oxygen sensor...
10-30-14, 09:34 AM
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p0171 keeps coming back even after replacing oxygen sensor...
Hi,
I have a 99 ES300 with 130K and I was getting p0171 error code and had my upstream oxygen sensor replaced with a high quality Bosch part. Now its coming again after drive for only a few miles. Its coming up twice on the scanner.
Any ideas what might the culprit be and any solutions?
Thanks!
P.S. Car drives fine and I'm not noticing any changes in performance.
I have a 99 ES300 with 130K and I was getting p0171 error code and had my upstream oxygen sensor replaced with a high quality Bosch part. Now its coming again after drive for only a few miles. Its coming up twice on the scanner.
Any ideas what might the culprit be and any solutions?
Thanks!
P.S. Car drives fine and I'm not noticing any changes in performance.
10-30-14, 09:58 AM
#2
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What you call High quality, does not mean that the part is compatible. When it comes to these sensors it's best to replace them with OE components.
Of course you could be having other issues. Wiring for example.
Phil
Of course you could be having other issues. Wiring for example.
Phil
10-30-14, 11:54 AM
#3
First, have you cleaned and checked-out the the MAF sensor? If it is not the MAF sensor, I bet a million bucks it's the Bosch sensor. Put in the correct Denso sensor and you will be good to go.
10-30-14, 01:22 PM
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@artbuc - whats the best way to clean the maf sensor? i remember seeing a spray can at the auto store for maf cleaning but it said on there not to use for lexus vehicles.
10-31-14, 01:20 AM
#5
Even if it is a dirty MAF sensor, I suggest you still replace the Bosch sensor. It could be a constant source of headache. I believe the 99 ES uses only A/F sensors (aka wide-band O2 sensors) upstream. The 98's used A/F sensors upstream for Calif emissions spec cars and regular O2 sensors upstream for non-Calif cars.
http://us.lexusownersclub.com/forums...th-1999-es300/
Last edited by artbuc; 10-31-14 at 01:56 AM.
11-17-14, 03:05 PM
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ok so i cleaned the maf but no luck. i'm going to change the bosch sensor to a denso one. is this the right one to buy (front, upstream) - http://www.rockauto.com/catalog/more...708&cc=1387054
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11-18-14, 01:15 AM
#8
ok so i cleaned the maf but no luck. i'm going to change the bosch sensor to a denso one. is this the right one to buy (front, upstream) - http://www.rockauto.com/catalog/more...708&cc=1387054
11-19-14, 06:58 AM
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11-19-14, 07:00 AM
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11-19-14, 12:09 PM
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11-19-14, 09:50 PM
#14
A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain.
So, possible solutions include:
Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace/repair as required
Inspect all hoses and connections in the air intake system
Inspect and/or test the intake manifold gaskets for leakage
Check for a dirty fuel filter and proper fuel pressure
Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool
If you have access, you may want to run a smoke test
Read more at: http://www.obd-codes.com/p0171
Copyright © OBD-Codes.com
So, possible solutions include:
Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace/repair as required
Inspect all hoses and connections in the air intake system
Inspect and/or test the intake manifold gaskets for leakage
Check for a dirty fuel filter and proper fuel pressure
Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool
If you have access, you may want to run a smoke test
Read more at: http://www.obd-codes.com/p0171
Copyright © OBD-Codes.com
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