Camshaft Position Sensor’s Top Dead Center (TDC) calibration

phonic wheel learning

From the UK/Euro owner’s manual (the battery replacement section actually appeared on the next page, and I pasted it in for relevance)

Phonic wheel learning procedure: 

 Let the engine run until the Cold-Engine (blue) light turns off – rev the engine min. 3 times up to 6000 rpm (the manual implies that you only need to do this once?) and let the RPM drop to idle in between – wait one minute, turn engine off, wait one minute, turn it on, wait one minute – this should store the phonic wheel values, and prevent getting intermittent misfire errors (including P0300/P0302/P0303), triggering the “Check Engine” light. 

The UK/Euro owner’s manual specifies that a “phonic wheel learning procedure” is to be performed “every time the battery is reconnected after being disconnected”. There is no mention of this in our North American manual, which casts a doubt as to whether this is carryover from older FIAT manuals, or is in fact true for our 1.4 L engine.

Although it makes perfect sense after a timing belt change, in order to calibrate/re-initialize the Camshaft Position Sensor’s TDC for the spark timing in the ECM, I doubt that this normally needs to be done just because the battery has been disconnected. I’d love for some experts to chime in: Is this a helpful tip, or is it simply another mistake by FIAT’s technical writers?

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