Hello all...I really need some expert tech assistance.

1998 Accord 2.3 EX

After two failed installations of after market cam position sensor, I sprung for the oem version by Denso. Installed, no check engine light, no more limp mode. Life is good.

Take it out on its first 20 mile run not running AC, so I can listen, observe any engine issues . Get within a mile of home, decide to turn AC on. Shortly thereafter check engine light for P1381 (cam position sensor) comes on.

By now, im out of my mind having done this job 3x in a row, certain that oem was the answer.

Could the source of my problem be in the ECM? Please share your answers...its my daily driver and im in desperate dire straits.

 

The CYP sensor is in the distributor.

On your generation Accord, P1381 can also be caused by electrical interference from an alternator with faulty diodes.

This attached excerpt is from a Honda Service New article.

 

THANK you so very much for this informative reply. Failing diodes in the alternator make more sense than ever as the root cause of this problem. My turning on the AC in the last mile of an otherwise successful 20 mile test run explains higher electrical consumption and an intermittent interruption to cam sensors; ( mine located behind crank pulley at base of timing belt cover)

Im going to follow this service bulletin to the letter and will report back. A new alternator would be a cake walk compared to a 4th attempt at changing out cam sensors.

​​​​​​​My complete gratitude for charting a new course on this mind numbing dilemma.

 

On your car, P1381 is Cylinder Position (CYP) Sensor, which is in the distributor.

The Crankshaft Position Sensor (CKP)/Top Dead Center (TDC) Sensor is near the crank pulley.

 

You would not believe the journey i have been on since July . No where along the way has anyone suggested that failing diodes in an alternator could be tripping the p1381 code.

After a trip to auto parts store to check my perfectly charging alternator, low and behold it showed diodes FAILED. That was about the best news ever. So I bought new alternator, and though I have not been on a good test drive, no cel .

The car is (slightly) revving up and down at idle. I know this is completely unrelated, but could the failing diodes have caused the engine to muck up the idle air control? Is the revving up and down a symptom of a bad or dirty iac?

Im almost to the finish line..
Thanks for your reply...

 

I know this thread is a little old, so this reply is for the benefit of those who are searching for fix to their P1381 code. I have a 1998 Accord 2.3 LX, F23A1 engine and replaced the distributor with a known, good unit from a 2001 Accord I owned. Nope, stil popped the code. I ran across this thread and I initially thought, "yeah, right, the alternator is popping a misfire code", I just knew I was going to be chasing a short somewhere in the engine ecu harness. As easy as it is to pull the alternator and take it down to the parts store for testing, this was something I at least had to eliminate as a possibility. Well, what do you know, FAIL with old alternator, replaced with a good used unit and no more misfire code. I would have NEVER considered the alternator were it not for this thread. Hope this helps someone else struggling with the same issue. Thanks, for posting!

 

Hello, I just wanted to further add to this thread for the sake of others who may research this issue in the future. The alternator fixed the issue for me.

I had the same issue on my 2001 Honda Accord, 2.3L, 4 cylinder, F23A4 engine, 272k miles. I replaced the alternator and so far have driven over 150 miles and no Check Engine light and no engine surging or driveability issues whatsoever. Previously the CE light would come back on within a few miles of driving, and the surging/drivability issues would start happening within anywhere between 5~30 miles and continue at random for the duration of the drive (my commute is 1 hr+).

I was trying to avoid sending in the ECM, due to both cost and the fact that my commuter vehicle would be out of commission during that time, and some research (including this forum thread) showed that a faulty alternator could cause the suspect sensor to malfunction, triggering the code and other driveability issues...so I decided to try replacing the alternator, especially since I could return it for a refund if it did not solve the issue. I don't usually like to throw parts at the car and I always try to avoid doing that, but sometimes it is the best option, especially when it is a part that is fairly easy to access and replace on the vehicle. Luckily the issue was fully solved by the new alternator.