Resetting ECU after O2 sensor replacement?
12-30-2013, 07:20 AM
#1
Advanced
Thread Starter
Resetting ECU after O2 sensor replacement?
Gentlemen,
Does the ECU needs to be reset after replacing the sensor?
If so, are there specific steps or is it just a matter of disconnecting the battery for a while?
Does the ECU needs to be reset after replacing the sensor?
If so, are there specific steps or is it just a matter of disconnecting the battery for a while?
12-30-2013, 08:28 AM
#2
Rennlist Member
87+ certainly yes. For the 85-86 ECU's I don't think there is any stored adaptation for the O2-sensor but it can't hurt to reset it, just disconnect the battery for a minute or so.
12-30-2013, 10:41 AM
#4
Team Owner
If you are working on a pre 87 system,
then you should check the MAF calibration after fitting any of these parts,
MAF, O2 , Porken chipset, ISV
Porken makes a device called a Blinker for doing this.
As posted no info is stored on pre 87 injection systems,
so a battery reset won make any changes
then you should check the MAF calibration after fitting any of these parts,
MAF, O2 , Porken chipset, ISV
Porken makes a device called a Blinker for doing this.
As posted no info is stored on pre 87 injection systems,
so a battery reset won make any changes
Trending Topics
12-31-2013, 04:00 AM
#9
Team Owner
Jeff changing parts of the injection system sensors will be more effective if a battery reset is done,
so the system will relearn the new parts parameters as whole,
as opposed to swapping in one new part and then driving the car,
so the system will relearn the new parts parameters as whole,
as opposed to swapping in one new part and then driving the car,
12-31-2013, 02:10 PM
#11
Rennlist Member
You see this adjusting within moments short term, and a few miles long term.
Resetting the ECU removes ALL trim, and the SAME trim adjustment still needs done.
Just wondering that since the same work to trim from the factory map (which will never have zero trim) needs done, what's that doing more of?
The trim is gonna get to (imaginary number) +1.5% just as fast, either way.
12-31-2013, 03:18 PM
#12
Instructor
Join Date: Jul 2012
Location: MT
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
There may be a difference between reseting and what I'm refering to then. A post from another thread:
"As we all know, our cars have PCM’s {power control modules .LH EZK) which are computers. Any computer needs memory to function properly. There are several kinds of memory. PROM (program read only memory) and ROM (read only memory). They hold (library) the basic set of instructions (map) on how the input from sensors (O2, RPM, MAF) will be handled, and also vehicle specified data (weight, axle ratio, engine type, etc.
Maps are programs stored in the PROM and ROM. Maps are a set of instructions for different driving conditions. An example: if you push the gas pedal to the floor the PCM knows the car is under a load by inputs from the RPM, MAF, and TPS sensors, for these set of conditions the PCM will advance the cars timing.
RAM (random access memory) and KAM (keep alive memory) is where temporary information from sensors is stored, updated and rearranged. It’s a journal of driving and operating conditions that have been recorded. Fault codes are also stored in RAM and KAM. Even though the PCM has a map, it also has the ability to relearn new strategies. It learns from systems or sensor failures. An example would be the 02 sensor, having a lazy reading due to age. The PCM “looks up tables” (map) to find the adaptive setting for fuel injector pulse and timing. The PCM can’t compensate for a total electronic or mechanical failure. This information is stored in the KAM as fault codes. If the battery were disconnected in this example the adaptive strategies would be lost on startup, which would cause a rich or lean drivability problem until the PCM reads the O2 sensor is out of range and adapts to its new setting.
928 S4’s have adaptive memory strategy for idle speed and CO level. Porsches exact words are “Due to the storage of carried-out curve displacement in the memory, the engine will have to be run about 10 minutes at first after an interruption of the permanent pulse to the control unit, e.g. caused by disconnecting the battery or pulling off the 35-pin plug on the injection control unit, which cancels the displacement, in order to permit correct adaptation to the nominal values.”
If any electronic sensors on the motor, which would set a code, were changed the keep alive adaptive memory would have to be erased for the PCM to return to its factory map setting. If you don’t have a scan tool that can clear codes, you should disconnect the battery and touch the disconnected negative cable end to the batteries positive disconnected cable end. This will discharge any capacitors in the system and remove the adaptive information stored in the KAM.
In conclusion, disconnecting the battery on any computer control vehicle will have an adverse effect on the vehicles performance until it has relearned its adaptive strategy or map values.
Steve C
The great white"
"As we all know, our cars have PCM’s {power control modules .LH EZK) which are computers. Any computer needs memory to function properly. There are several kinds of memory. PROM (program read only memory) and ROM (read only memory). They hold (library) the basic set of instructions (map) on how the input from sensors (O2, RPM, MAF) will be handled, and also vehicle specified data (weight, axle ratio, engine type, etc.
Maps are programs stored in the PROM and ROM. Maps are a set of instructions for different driving conditions. An example: if you push the gas pedal to the floor the PCM knows the car is under a load by inputs from the RPM, MAF, and TPS sensors, for these set of conditions the PCM will advance the cars timing.
RAM (random access memory) and KAM (keep alive memory) is where temporary information from sensors is stored, updated and rearranged. It’s a journal of driving and operating conditions that have been recorded. Fault codes are also stored in RAM and KAM. Even though the PCM has a map, it also has the ability to relearn new strategies. It learns from systems or sensor failures. An example would be the 02 sensor, having a lazy reading due to age. The PCM “looks up tables” (map) to find the adaptive setting for fuel injector pulse and timing. The PCM can’t compensate for a total electronic or mechanical failure. This information is stored in the KAM as fault codes. If the battery were disconnected in this example the adaptive strategies would be lost on startup, which would cause a rich or lean drivability problem until the PCM reads the O2 sensor is out of range and adapts to its new setting.
928 S4’s have adaptive memory strategy for idle speed and CO level. Porsches exact words are “Due to the storage of carried-out curve displacement in the memory, the engine will have to be run about 10 minutes at first after an interruption of the permanent pulse to the control unit, e.g. caused by disconnecting the battery or pulling off the 35-pin plug on the injection control unit, which cancels the displacement, in order to permit correct adaptation to the nominal values.”
If any electronic sensors on the motor, which would set a code, were changed the keep alive adaptive memory would have to be erased for the PCM to return to its factory map setting. If you don’t have a scan tool that can clear codes, you should disconnect the battery and touch the disconnected negative cable end to the batteries positive disconnected cable end. This will discharge any capacitors in the system and remove the adaptive information stored in the KAM.
In conclusion, disconnecting the battery on any computer control vehicle will have an adverse effect on the vehicles performance until it has relearned its adaptive strategy or map values.
Steve C
The great white"
