Issues with my tune/O2 sensor
10-07-2009, 07:20 PM
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Issues with my tune/O2 sensor Today my check engine light came on and I noticed after that that my shifts seemed softer than usual. The car was running fine though and the trans' didn't seem to be slipping. I took it by Advanced and had them scan it for me. I got the codes: P0135, P0140, P0160, P0405. I know one of those is for one of the front O2's and the others are for emission stuff. I've had the EGR and rear O2 codes turned off by my tuner. It's not possible to loose my tune if my battery never died or anything right? I think the computer goes into whats called open loop when one of the front O2 goes bad? Would that cause the computer to revert back to like a "default" tune? Which would explain the emissions codes coming back and the softness in my shifts again. When I replace the sensor is my tune going to come back? Thanks.
Last edited by CayenneRedV6; 10-07-2009 at 09:28 PM.
10-07-2009, 09:34 PM
#2
http://www.obd-codes.com/p0135
This is sensor 1, bank 1. Driver's side, front, which you have to have. See the link on how to troubleshoot/repair the issue.
http://www.obd-codes.com/p0140
P0160 -- O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
P0405 -- EGR position sensor circuit low voltage
These should have all been turned off by your tuner. Your rear sensors (Sensor 2) should not set a code. Nor should the EGR.
There is no way they could be present if he had disabled them. A disconnected or dead battery will not loose the settings of the tune.
This is sensor 1, bank 1. Driver's side, front, which you have to have. See the link on how to troubleshoot/repair the issue.
http://www.obd-codes.com/p0140
P0160 -- O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
P0405 -- EGR position sensor circuit low voltage
These should have all been turned off by your tuner. Your rear sensors (Sensor 2) should not set a code. Nor should the EGR.
There is no way they could be present if he had disabled them. A disconnected or dead battery will not loose the settings of the tune.
10-08-2009, 11:16 AM
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I figured that loosing power wouldn't make the computer loose it's tune. That's why I'm confused. All of those codes except the front O2, obviously, where turned off. My thinking is that the bad front O2 has caused the computer to go into some sort of "safe mod" where all those emissions codes are still turned on. I guess I'll find out when I replace that O2 sensor and reset the codes.
10-08-2009, 11:29 AM
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I got this answer somewhere else:
" Your tune is wrote into the pcm, it wont got away, or change by disconnecting your battery. Your fuel trims will be reset by changing your battery, but thats normal. Some codes will put your car into a limp mode almost, depending on the code it can effect line pressure, a/f ratio, timing, and several other things in the tune. Best thing is to do get the O2 sensor changed unhook your battery for atleast 30mins and your go to go. It aslo depends on how the codes were cut off if they will show up with a scan tool or not, just because they were in the scan tool doesnt mean they came back, they probably just werent turned all the way off properly."
I didn't know some of that, it makes more since now. Thanks.
" Your tune is wrote into the pcm, it wont got away, or change by disconnecting your battery. Your fuel trims will be reset by changing your battery, but thats normal. Some codes will put your car into a limp mode almost, depending on the code it can effect line pressure, a/f ratio, timing, and several other things in the tune. Best thing is to do get the O2 sensor changed unhook your battery for atleast 30mins and your go to go. It aslo depends on how the codes were cut off if they will show up with a scan tool or not, just because they were in the scan tool doesnt mean they came back, they probably just werent turned all the way off properly."
I didn't know some of that, it makes more since now. Thanks.
10-08-2009, 05:22 PM
#5
I got this answer somewhere else:
" Your tune is wrote into the pcm, it wont got away, or change by disconnecting your battery. Your fuel trims will be reset by changing your battery, but thats normal. Some codes will put your car into a limp mode almost, depending on the code it can effect line pressure, a/f ratio, timing, and several other things in the tune. Best thing is to do get the O2 sensor changed unhook your battery for atleast 30mins and your go to go. It aslo depends on how the codes were cut off if they will show up with a scan tool or not, just because they were in the scan tool doesnt mean they came back, they probably just werent turned all the way off properly."
I didn't know some of that, it makes more since now. Thanks.
" Your tune is wrote into the pcm, it wont got away, or change by disconnecting your battery. Your fuel trims will be reset by changing your battery, but thats normal. Some codes will put your car into a limp mode almost, depending on the code it can effect line pressure, a/f ratio, timing, and several other things in the tune. Best thing is to do get the O2 sensor changed unhook your battery for atleast 30mins and your go to go. It aslo depends on how the codes were cut off if they will show up with a scan tool or not, just because they were in the scan tool doesnt mean they came back, they probably just werent turned all the way off properly."
I didn't know some of that, it makes more since now. Thanks.
Limp mode is designed to get the vehicle to the mechanic w/o damaging or stopping the vehicle any more. I have been in a couple that went into limp mode, and it was very noticeable. But neither was a GM, much less an fbody.
10-09-2009, 03:16 PM
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The sensors are less than a year old so I looked the wire over yesterday to see if it had gotten melted by the exhaust or something. The wire looked fine so I reset the computer and drove the car around today. The check engine light didn't come back on. Not sure what the deal is but if the light comes back I'll replace the sensor.
