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my 2012 acura tsx SE auto 104,000 miles electronic power steering light came on after i installed used automatic transmission. i figured since i separated the engine,transmission and cradle from the body that it needed programming. so i programed it and followed the handheld procedures. light stayed off two weeks and popped on while driving in town. i could turn off car and crank it while rolling to eliminate the persistent steering wheel light. the eps light started gradually coming on more often after reseting it...either by disconnecting the battery or turning off ignition. ive taken it to acura to let them install the eps control unit, but it didnt fix the problem. they said of course that it needed new gear rack and labor...around 3600$ my eps light has been solid for 5 months. arms are strong as hell now! my 2 codes are 71-01 motor angle sensor(sin/cos signals) 22-01 engine speed signal. i dont expect anyone to have a solid simple answer to fix my issues, i am taking suggestions and ideas to attempt one last try at fixing the issue myself. thanks
 

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The 71-01 is a running diag indicator, and since the initial diag 71-02 is not present I would take that as a sign that the signal is weak, but the base connection via the initial diag is not indicated as a complete fail of the sensor circuit. The angle sensor itself appears to be pretty simple with 6 pins and 3 coils, so that it is easy to make some good assessments with just a multimeter across the pins on the 28 pin connector at the EPS control unit (or the sensor connector at the rack itself). Given the rack removal and therefore the connector removal it is likely that the steering angle sensor DTC is related to a pin in the connector vs an internal sensor failure in the rack.

I think I would probably start with disconnecting the connector at the EPS controller and measuring the 3 coils for the angle sensor, and then disconnecting the angle sensor connector at the rack, depinning the connector and cleaning and adjusting the pins to seat well. The sine and cosine return signals are going to be more susceptible to connector issues.

The 22-01 DTC is a little more subtle. It appears that it is a passive copy of the crank pulse signal, which could imply that a weakened crank signal is strong enough to be read correctly at the ECM, but the copy sent to the EPS controller is weakened, especially during a cranking start. Not really sure what to make of that one, but since it is an initial diag, it is likely that it could prevent the EPS from engaging to provide assist. Given that the crank sensor cover is removed during transmission replacement and that there is a warning about damaging it, I would suspect that is likely to have been affected during the trans swap. It would also likely have a different result during a rolling restart, with a warmer engine and a likely different voltage drop.
 

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my 2012 acura tsx SE auto 104,000 miles electronic power steering light came on after i installed used automatic transmission. i figured since i separated the engine,transmission and cradle from the body that it needed programming. so i programed it and followed the handheld procedures. light stayed off two weeks and popped on while driving in town. i could turn off car and crank it while rolling to eliminate the persistent steering wheel light. the eps light started gradually coming on more often after reseting it...either by disconnecting the battery or turning off ignition. ive taken it to acura to let them install the eps control unit, but it didnt fix the problem. they said of course that it needed new gear rack and labor...around 3600$ my eps light has been solid for 5 months. arms are strong as hell now! my 2 codes are 71-01 motor angle sensor(sin/cos signals) 22-01 engine speed signal. i dont expect anyone to have a solid simple answer to fix my issues, i am taking suggestions and ideas to attempt one last try at fixing the issue myself. thanks
Letter from American Honda I received August 2019.
EPS control unit warrantied for 15 years from original date of purchase, no milage limit.
If you already paid for replacement, you may be eligible for reimbursement.
I am "surprised" that Acura did not inform you of the warranty extension.
American Honda Customer Support and Campaign Center contact number is (888) 234-2138
 
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