My 09 Road King Classic won't start. The fuel pump primes and it cranks but it won't start. It is throwing a P0374 code (CKP sensor sync error).

The bike is less than a year old. It seems unlikely that the crank position sensor would have gone bad already, or could it?. Is this a known problem?

 

Look for a short or a loose wire. Although, it could be a faulty CKPS. Their is the fluke factor to consider.

 

I checked my crank sensor according to Haynes manual:
disconnect harness from computer, connect multitester to wires in AC mode. I think it should be around 2V when starter cranks engine. But mine is 99, so your bike can have different procedure.
1 mOhm or less sensor resistance for 2000

 

I know this is an old thread, but I just ran into the same issue myself and want to share my fix.

My bike (05 FLHRCI) was throwing P0373. After replacing my crank sensor and still having the same issue plus P0374 I eventually figured out it is the bike's ON/OFF/ACC switch on the dash. If I wiggle it slighty, boom, bike works.

Hope this helps someone out there.

 

Failz, thank you, thank you, thank you,


I planned to do a Sunday ride today and bike wouldn't start (rode 200 miles yesterday) like Philly explained. I used HD electrical diagnostic manual(a must have now a day's, next to regular service manual) after following the troubleshooting guide I figured it was the sensor. At the end of flow chart they mention TMAP. Why is this mentioned all of a sudden? Anyway time to contact "The G" (Google) I searched P0374, and at the top was your recent response here. So I tried your advice and BOOM, she came to life. Now, I must say, I'm not sure if it was the ACC switch or the Cruise enable switch. My next step is to remove fairing and check switches. I did have a intermittent problem last year with my cruise not functioning properly because of switch.


But ya, you did help someone.

 

Good info and nice bike Failz!

 

Glad you were able to fix it before it got expensive/time consuming!

 

The tmap is referenced because in the ecm there are correlations between pressure and tp

I recently had one with the sync code and it was a wire at the tmap. It was the ground wire broken in the insulation. Also thought it was ice cold because the ground opened the Iat circuit.

Symptom was crank, no start, seemed rich, when got started ran rich

 

Hey guys,

I got the P0374 code the bike cranks and starts but dies after a while I replace the crankshaft position sensor and the bike still starts and runs for a little bit but dies out eventually I have change the spark plugs and in the O2 sensors but that still does the same thing do you guys have any tips I have checked the battery connection I’ve also clean the ECM connections and lastly replace the crank shaft position sensor what else do you think it might be guys?

 

Only thing I can think of , is to pull the ignition switch and check the connection behind it . You could have a build up of corrosion or a damaged wire . Some of the older , or maybe it's the newer ( not sure ) can be taken apart and cleaned , the points get corroded and lose contact , which could be the reason why your bike is stalling .