Bad O2 sensor or something else? (picture)
Thread Starter
Launching!
Joined: Jun 2004
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From: Belle Vernon, PA
Bad O2 sensor or something else? (picture) I was doing some logging today and noticed that my O2 sensors are way off in comparison with each other. Could this be a bad O2 or something worse?
Thread Starter
Launching!
Joined: Jun 2004
Posts: 264
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From: Belle Vernon, PA
Anyone? This was a WOT run, and I thought the O2s should be between 890 and 900. I don't think it's a bad injector since they are both reading the same. I am getting a few codes P0134, P0135, and P0155 so it could very well be a bad O2.
Also, I still can't get into F'n closed loop so I have no idea what my LTFT's look like.
Also, I still can't get into F'n closed loop so I have no idea what my LTFT's look like.
TECH Senior Member
Joined: Nov 2001
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From: Lake Zurich, IL
P0155 Heated Oxygen Sensor Heater Circuit (bank 2, sensor 1)
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
P0135 HO2S Heater Circuit Bank 1 Sensor 1
These codes will prevent you from going into Closed loop... (they force you to stay in open loop, so you're running off pre-determined tables ... no fuel trim learning) you definetly have a problem (SES lights only go on if there's a problem
)
When did these codes start? did you make any changes before they started? (such as headers?)
Check the "Engine Sensor" fuse (it's under the hood) to make sure it's not blown
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
P0135 HO2S Heater Circuit Bank 1 Sensor 1
These codes will prevent you from going into Closed loop... (they force you to stay in open loop, so you're running off pre-determined tables ... no fuel trim learning) you definetly have a problem (SES lights only go on if there's a problem
)When did these codes start? did you make any changes before they started? (such as headers?)
Check the "Engine Sensor" fuse (it's under the hood) to make sure it's not blown
Thread Starter
Launching!
Joined: Jun 2004
Posts: 264
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From: Belle Vernon, PA
Originally Posted by horist
P0155 Heated Oxygen Sensor Heater Circuit (bank 2, sensor 1)
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
P0135 HO2S Heater Circuit Bank 1 Sensor 1
These codes will prevent you from going into Closed loop... (they force you to stay in open loop, so you're running off pre-determined tables ... no fuel trim learning) you definetly have a problem (SES lights only go on if there's a problem )
When did these codes start? did you make any changes before they started? (such as headers?)
Check the "Engine Sensor" fuse (it's under the hood) to make sure it's not blown
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
P0135 HO2S Heater Circuit Bank 1 Sensor 1
These codes will prevent you from going into Closed loop... (they force you to stay in open loop, so you're running off pre-determined tables ... no fuel trim learning) you definetly have a problem (SES lights only go on if there's a problem
)When did these codes start? did you make any changes before they started? (such as headers?)
Check the "Engine Sensor" fuse (it's under the hood) to make sure it's not blown
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Originally Posted by black_ws6
If I turn those codes off will that let it go into closed loop?
check the Engine Sensor fuse
Also did you make ANY changes to the car before you started receiving these codes?
(Don't just turn them off... they are indicitive of a problem... need to fix that problem first)
Thread Starter
Launching!
Joined: Jun 2004
Posts: 264
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From: Belle Vernon, PA
Originally Posted by horist
yes... but since those codes are being set, there's a problem and if it is a bad O2 the fueling adjustments will be way off...
check the Engine Sensor fuse
Also did you make ANY changes to the car before you started receiving these codes?
(Don't just turn them off... they are indicitive of a problem... need to fix that problem first)
check the Engine Sensor fuse
Also did you make ANY changes to the car before you started receiving these codes?
(Don't just turn them off... they are indicitive of a problem... need to fix that problem first)
Also, my TPS shows at 100% sometimes and other times it is around 80-90%. I checked to make sure nothing was getting in the way, and I also checked the throttle body at WOT and it is opening all the way. I think the sensor may be going bad as well.
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This was WOT so forget closed loop. Those O2 voltages
are both pretty low for properly enriched. You want to
judge your O2s' health by the frequency and evenness
of their switching at idle & light cruise (bearing in mind
any problems from headers etc.), not voltage. I don't
believe any of the O2 codes would give you a lean-out
effect. Even fuel trimming will only enrich against the
base settings, not subtract fuel at WOT.
Air leaks near the sensor can depress O2 readings, so
can misfires that let unburned air / fuel into the back
pipe. Or, just a way lean WOT mixture.
It only takes abother point or two of mixture to swing
the narrowbands from 0.6x to 0.8V. But that is at a
mixture point where you don't want to be at WOT,
if it is indeed true.
And that is the $320 wideband question.
are both pretty low for properly enriched. You want to
judge your O2s' health by the frequency and evenness
of their switching at idle & light cruise (bearing in mind
any problems from headers etc.), not voltage. I don't
believe any of the O2 codes would give you a lean-out
effect. Even fuel trimming will only enrich against the
base settings, not subtract fuel at WOT.
Air leaks near the sensor can depress O2 readings, so
can misfires that let unburned air / fuel into the back
pipe. Or, just a way lean WOT mixture.
It only takes abother point or two of mixture to swing
the narrowbands from 0.6x to 0.8V. But that is at a
mixture point where you don't want to be at WOT,
if it is indeed true.
And that is the $320 wideband question.
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