do u have to unhook the battery when u unhook any sensor
- Thread starter interex1982
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mo_dingo
Dirt-Old 20+Year Member
It's a good idea, just in case spark decides to jump around when you are plugging in the new sensor.
But also, the computer needs to know it has a new sensor, so it's a good idea to reset comp.
Scott
But also, the computer needs to know it has a new sensor, so it's a good idea to reset comp.
Scott
MLC Stang
Founding Member
The answer is absolutely YES, IF the sensor that you have disconnected is BAD. (e.g. you are replacing a known bad sensor that has stored a trouble code in the computer.)
If you are just disconnecting a good sensor to get at something else in the process of doing other work, then the answer is NO.
Here’s why:
A bad sensor will set and store a trouble code in KAM (Keep Alive Memory) in your car’s computer. If you then replace the bad sensor with a new one and drive the car, without clearing the KAM, the new sensor is IGNORED! It is ignored because the trouble code for that sensor is still set and the computer will continue to use the limp-home mode default settings for that sensor. That’s called the Failure Effects Management feature of your car’s computer.
In order to get the computer to start using the input from the NEW sensor, you MUST clear the KAM and get rid of that trouble code.
The KAM is cleared by disconnecting the negative terminal of your battery for at least 5 minutes. That will remove power from your computer and allow the KAM to decay and clear any stored trouble codes.
Keep in mind that for the first 10 miles or so of driving after you clear the KAM, your car will run a bit funky until it relearns all of the input from the sensors again.
If you are just disconnecting a good sensor to get at something else in the process of doing other work, then the answer is NO.
Here’s why:
A bad sensor will set and store a trouble code in KAM (Keep Alive Memory) in your car’s computer. If you then replace the bad sensor with a new one and drive the car, without clearing the KAM, the new sensor is IGNORED! It is ignored because the trouble code for that sensor is still set and the computer will continue to use the limp-home mode default settings for that sensor. That’s called the Failure Effects Management feature of your car’s computer.
In order to get the computer to start using the input from the NEW sensor, you MUST clear the KAM and get rid of that trouble code.
The KAM is cleared by disconnecting the negative terminal of your battery for at least 5 minutes. That will remove power from your computer and allow the KAM to decay and clear any stored trouble codes.
Keep in mind that for the first 10 miles or so of driving after you clear the KAM, your car will run a bit funky until it relearns all of the input from the sensors again.
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