Crank Sensor
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Not sure if that has been up for discussion before. I would think a relearn would not be needed, but then again, I'm not sure.
The 2008 Service Manual indicates a variation relearn is required after the following procedures:
1. Engine replacement.
2. Engine Control Module (ECM) replacement.
3. Crankshaft damper replacement.
4. Crankshaft replacement.
5. CKP sensor replacement.
6. Any engine repairs which disturb the crankshaft to CKP sensor relationship.
#6 might answer your "why" question.
A lot of scan tools are now capable of supporting a crank relearn, so a trip to a Dealer isn't always necessary.
The 2008 Service Manual indicates a variation relearn is required after the following procedures:
1. Engine replacement.
2. Engine Control Module (ECM) replacement.
3. Crankshaft damper replacement.
4. Crankshaft replacement.
5. CKP sensor replacement.
6. Any engine repairs which disturb the crankshaft to CKP sensor relationship.
#6 might answer your "why" question.
A lot of scan tools are now capable of supporting a crank relearn, so a trip to a Dealer isn't always necessary.
Thanks, #6 is kind of what has me confused.... If the reluctor ring or tone ring didn't change position on the crank itself, it would still send the signal through the sensor to the ECM at the same time as the old sensor,which would trigger the other sensors when to send fire or squirt signals to their parts of the process....What has me is I don't see how a sensor replacement with the exact same sensor would change anything in the timing sequence. It would change pulse only when the larger tooth or wider space on the ring when by the sensor. ...
System description from the Manual:
The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the CKP sensor. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load. The ECM stores the CKP system variation values after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set.
Hope that helps.
The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the CKP sensor. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load. The ECM stores the CKP system variation values after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set.
Hope that helps.
System description from the Manual:
The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the CKP sensor. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load. The ECM stores the CKP system variation values after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set.
Hope that helps.
...Clear as a bell..lol... I've also read in a couple of places I looked is that you can unhook the battery for a while (at least an hour or more) and the system drains it's power and will do a relearn on it's own when you hook up the battery again. Any truth to that??I'm doing a Seafoam flush to hopefully help with a P0017 code,so when I drain the oil,I wanted to clean the VVS, cam sensor and crank sensor. But I don't want to open up another can of worms if I pull the crank sensor.
All of the info that I have run across indicates that you need a scan tool to initiate a relearn. Disconnecting the battery is not going to erase the memory in the ECM. I do remember one guy reported that he replaced a CKP sensor and got away without a relearn. That might have been just luck.
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