CKF Bypass Trick

UPDATE 10/07/09
A poster by the name of William pointed something wrong with the CKF bypass trick information posted here, and well, it’s now time for yet another CKF revision! Not sure how or why my information on this was slightly off, but this article has been revamped and should have a lot less people wondering why this trick isn’t working for them (yet it does for others? weird). What William pointed out will not only fix the Code 9 issues some of you are experiencing, but is the right way in performing the CKF bypass altogether. Thank you William.

UPDATE 2/19/09 (now superceded)
I’ve slightly revamped this page to better explain the CKF bypass trick due to the CEL 9 issue that has recently arisen. There are now two methods you can perform – but –  I HIGHLY suggest performing method 1 first then move onto method 2 (noted in red)  if you get a CEL code 9 once you’ve tried method 1. If you’re not getting a CEL code 9 with method 1 there is no need to perform method 2 – otherwise you may give yourself CEL 54 or 9 if you apply method 2 when it is not required.

UPDATE 9/3/08
There have been reported CEL CODE 9 (CYP) issues once the CKF bypass trick has been performed on certain OBD2 civic/integra vehicles. There is a fix for this problem which is explained within the procedures in RED below.

NOTE: You DO NOT need to perform the new method if you’re NOT getting CEL code 9!

SYNOPSIS

This article describes how to trick a U.S. OBD2a/b (96-01) Civic & Integra ecu into thinking a CKF sensor is wired in when there actually is no CKF sensor available.

What is the CKF sensor?

The CKF is the Crank Fluctuation Sensor. All U.S. 96-01 (OBD2) Honda/Acura vehicles have this sensor which is integrated onto the oil pump. (CKF images soon)

This trick is aimed to help hybriders who are using a U.S. OBD2a/b ecu in their vehicle (for whatever reasons) to power their engine – yet their motor is lacking a CKF sensor.

Here’s a few scenarios where this bypass trick comes in reeeal handy:

  1. When using a JDM OBD2 B-series engine in a U.S. 96-01 civic/integra powered by a U.S. OBD2 ecu. JDM engines do not have a CKF sensor on the oil pump like US OBD2 engines do. Some people want to stay smog & street legit; this bypass trick allows this very desired feature without needing to convert to OBD1. It’s also been proven that you CAN pass Smog and the state REF (here in CA) while this mod is in place – passes the OBD2 scanner tool.
  2. When using a U.S. OBD2 B-series engine in a 92-95 Civic/Integra powered by a U.S. OBD2 ecu (via jumper harness adapter). Same info from above applies here.

For the unknowing – when using a U.S. OBD2 ecu & the CKF sensor is not wired in, the engine will run like total crap not to mention you’ll get a nasty CEL (code 54). This trick basically taps the CKF into the CKP and shares the signal. This bypass trick will save you time, money (around $300), and severe headaches!

OBD2a Civic/Integra

Please refer to the ecu pin out page for the CKF pin location(s): OBD2a pin out schematics

Get yourself 4 Scotch-lock/tap splicers
Sometimes dubbed ‘quick splice’, these can be real life savers. Get 2 of these bad boys and a pair of pliers for the squeeze-splicing portion of the job:

Locate pinout C1 (CKFP) and C4 (CYPP) ; using the pliers quick-splice these two wires together as shown.
Now, cut C1 (blue wire w/red stripe) AFTER the quick-splice. This will sever the connection that leads to the actual CKF sensor out in the engine bay. This will allow C1 to piggyback the C4 signal properly and without issue.

Locate pin outs C1 & C4 quick splice C1 & C4

Locate pin C11 (CKFM) and C14 (CYPM) and quick-splice these two wires together as shown.
Now, cut C11 (white wire w/red stripe) AFTER the quick-splice. Doing this will  sever the connection that leads to the actual CKF sensor out in the engine bay. This will allow C11 to piggyback the C14 signal properly and without issue.

Locate pin C11 & C14 Quick-splice C11 to C14

The reason behind cutting  C1 and C11 AFTER the quick-splice, is to prevent conflicts with the ECU that may arise such as  CEL code 9 (CYP) and P-code 1337 (CSF sensor no signal).

FINALLY, RESET THE ECU BY UNPLUGGING THE ECU PLUGS FROM THE ECU FOR ONE FULL MINUTE OR PULL THE ECU (ie.BACKUP FUSE) IN THE ENGINE BAY FUSE BOX FOR ONE FULL MINUTE TO CLEAR THE ECU’S MEMORY.

That’s it!
Your finished OBD2a quick-splice job should look something like this:
OBD2a CKF mod complete.

OBD2b Civic/Integra

Please refer to the ecu pin out page for the CKF pin location(s): OBD2b pin out schematics

Locate the blue ecu plug “C”:

Locate OBD2b blue colored "C" plug

Now locate pinout C22 (CKFP) and C29 (CYPP) ; using the pliers quick-splice these two wires together as shown.
Now, cut C22 (blue wire w/red stripe) AFTER the quick-splice. Doing this will sever the connection that leads to the actual CKF sensor out in the engine bay. This will allow C1 to piggyback the C4 signal properly and without issue.

Locate pin C22 & C29 quick-splice C22 & C29

Then locate pin C30 (CYPM) and C31 (CKFM); quick-splice these two wires together as shown.
Now, cut C31 (white wire w/red stripe) AFTER the quick-splice. Doing this will sever the connection that leads to the actual CKF sensor out in the engine bay. This will allow C31 to piggyback the C30 signal properly and without issue:

Now locate pin C30 & C31 Quick-splice C30 & C31

The reason behind cutting  C22 and C31 AFTER the quick-splice, is to prevent conflicts with the ECU that may arise such as  CEL code 9 (CYP) and P-code 1337 (CSF sensor no signal).

FINALLY, RESET THE ECU BY UNPLUGGING THE ECU PLUGS FROM THE ECU FOR ONE FULL MINUTE OR PULL THE ECU (ie.BACKUP FUSE) IN THE ENGINE BAY FUSE BOX FOR ONE FULL MINUTE TO CLEAR THE ECU’S MEMORY.

That’s it!
Your finished OBD2b quick-splice job should look something like this:
OBD2b CKF mod complete.

PROPS

Special thanks to Honda-Tech member omahaturbocivic for THIS THREAD who exploited this trick – and anyone else (unmentioned) who thinks they’ve contributed to this! Also thanks to William for bringing up the required cutting after the quicksplice!

126 thoughts on “CKF Bypass Trick

  1. Leo,
    The CKF sensor is located on the oil pump, right near the crank pulley. You’ll have to raise up your car and remove your driver side wheel to gain better access to it. Here’s a pic:
    http://ff-squad.com/tech/sensors/ckf.jpg (d-series shown). OBD2 B-series is in the same location but is a 2-wire sensor. All you need to do is color match the 2-wires a B-series CKF sensor uses and disregard the 3rd wire (off your harness).

  2. Kent,
    Interesting info there.
    I’m not 100% sure if the CKF trick is causing ignition timing fluctuations. This is actually the first time someone has reported this to me. I mean, I could see how it could possibly affect ignition timing but a couple tests would need to be performed to single out if the CKF trick is actually causing this problem. Damn.

  3. Thanks for getting back to me Katman,
    Let me know what tests need to be performed and I can start to do them on my car so we can start compiling some data and see if the CKF trick is causing the ignition timing issue at idle or something else is. Thanks Katman

  4. Kent,
    No problem, but, the test would need to be performed on a car equipped with a working CKF sensor. The test would consist of monitoring ignition timing while the vehicle is running and CKF sensor plugged in and the second test would be to monitor ignition timing while the vehicle is running w/CKF trick in place.

  5. lol, yeah that is an obvious way to do it. I guess I just interpreted your response in meaning tests could be done on my system with the idle timing problem to determine if the CKF trick did it.
    If you are able to do such a test it would be great if you can share your findings (or anyone else reading this)
    maybe you can ask such a question for someone to do this test in the main CKF article?
    much appreciated

  6. Quick questions ..
    My friend has D16y7 obd2a a/t and he is going to use OBD1 p06 HONDATA s300 with OBD2A to OBD1 Conversion harness..(the car converted to MANUAL TRANSMISSION ..and Turbo)
    Does he need to trick CKF ?
    And what about IACV does it need to re pin?

  7. I am trying to do the same thing to my 01 prelude that i have dropped a jdm h22a in, which is replacing my usdm h22a1. I am currently using my h22A1 wiring harness, ecu, and intake manifold. I am using my jdm distributor with an internal coil. there are four wires coming from back of the motor by the oil pump that we have spliced into the distributor plug wires. Upon first start it idled about three minutes and died. THe car will stay running as long as i keep constant pressure on the pedal, but as soon as i let off, it dies. My car is not throwing any codes. Can you help me figure out what we have done wrong, or know where to access jdm wiring diagram or schematics? thanks

  8. Yo Katman…
    I bought at b18b1 obd2 its a japan made motor. the cks plug is diff than the ex harness…. im so confused the car wants to crank but there is no fuel going into it…. since the cks is not working, no i was using a p75 ecu then i re read the forum and i need a p72 ecu is that correct??? also should i use the same method wit c1 c4 c11 c14 if i plug the p72 in……. I need ur help bra……. thanks

  9. @ Angel
    If that’s a true JDM B18B non-VTEC DOHC engine, there shouldn’t be a CKF sensor on the oil pump (JDM engines don’t run a CKF sensor on the oil pump like US OBD2 motors do). Regardless, if your B18B engine DOES have a CKF on the oil pump, you need a 2-wire CKF plug from an OBD2 integra or 99-00 Si. 96-00 SOHC Civics all use a 3-wire CKF plug which needs to be switched out if going US OBD2 B-series. Whoever told you to run a P72 ecu is an idiot. You have the correct non-VTEC ECU (P75) to power your B18B engine. P72 is a GSR (B-series VTEC) ECU which would throw a check engine light for VTEC components you do not have on your B18B engine.

  10. OK so take the plug off the acura harness and wire it up to the harness on Sohc? I did that and the car still would not crank…. dude this is drivin me crazy!!! the crank sensor of the motor has two wires that are blue and white when i cut it off the harness the blue wire split into two wires the same blue and a brown wire so three wires where there. thats what makin me go bananas right now im starting to work on the car now hope to hear from u soon ill be checking back in every hour or so… thanks again

  11. Angel,
    Just color match the CKF wires from the integra harness to your civic harness and use the wires that match. If only one of them matches, use that one, then test the other two, whichever of the extra two wires work out…there you have it. If this doesn’t work for you, then perform the CKF trick as my article above explains.

  12. ok katman i have a d16z6 and i swapped everything off my old d16y8 motor on it except the oil pump if i use this trick since i have a obd2b ecu will my car start? i also got a d16z6 and a d16y8 obd2b dizzy plug from rywire…

  13. yo katman i have a 96 GSR integra i just dropped the jdm b18c1 im running a p72 ecu and im throwing a p1337 cfk code i did ur trick above but the check engine light is still on andi checked the codes again same thing…?does th cfk sensor pulg itself need to be sliced into something? please help

  14. Hey katman, I have an obd0 b16a block with b16a2 head , car is running, but I was getting code P 1337. manufacturer control. ignition system or missfire. when i start it. car seems to run fine, i googled the code, and im pretty sure it has to do with that sensor. i performed the bypass trick c1 to c4 and c11 to c14, but it didnt get rid of the code, however, i didnt reset the ecu, so ill try that. any suggestions? have you ever heard of this code? scanned it with one of those cheap orange 100 dollars obd2 scanners you buy from walmart. need help with this fast. thanks man

  15. Nevermind i think you have the the fix in red backwards. i depinned the c1 and c11 wires from the ecu, but then where does the CKF port on the ecu get its reading? no where. you need to cut the wiring AFTER the splice on the wiring side, NOT at the ECU side. so after you splice it together, c1 and c4 will be tied together with c1 cut AFTER the splice on the other side of the harness going towards the engine bay. same with c11 and c14, worked like a charm once i reversed the wiring.

  16. Yo Katman. I got my b18b started and it is an obd2 US MOTOR but im haveing a problem since the crank sensor wires where broken and i tried to color match the wires i get check engine light and when i plug my scan tool up it say cylinder sensor my question is what should i do to get that code off (code1383) and will i pass emissions? what should i do dude car runs like a champ new headers, blox im, password jdm intake, itr TB car is amazing but still cant figure out why the code if i performed the trick .

  17. katman i just performed the ckf bypass both ways on a jdm b18b1, and i’m now getting p1337 code. “csf sensor no signal” have you had any one else run into this problem and if so what should i do?

  18. katman pls tell me if this trick will work..
    i swaped 94 gsr engine in a 98 gsr body and got a cel i do belive its because the 98 body ecu thinks that ckf is not working when i dont have one on the 94 engine so its throwing a cel….if thats the case would this trick work
    pls let me know thanks

  19. Hey I have a 97 accord and I put a 94 bottom end on the stock motor a had in it..
    so I have the OBD2a head, wiring harness and ECU but the OBD1 block so I dont have a CKF sensers on it..
    It wont start and im pretty sure thats the poblem do you think your trick thing would work for me??
    and if so would the wires be the same as the diagram you have for the civic ecu??
    Thanks for any help you can give me..

  20. Katman,
    If i understand correctly the obd1 ckp is read through the distro. And if you swap into an ek that has a ckp on the crank why couldnt you just splice into the wires from the distro insead of at the ecu pins wouldnt it read the same since you are still using the same plug and harness?? But to help out with some peoples in here you can also use a harness converter from 0bd2a or obd2b to obd1 and you will not have to worry about a ckp code even again

  21. Katman, I have a problem with my stock 99 civic si popping CKF sensors… will this fix that and bypass the sensor and allow the car to run properly? Right now it keeps throwing a P0366 and will not rev past 3500rpm.

  22. So i did the trick and the light gos off after the car has been turned off for a few mins but after a couple secs after i start it the light comes back on. ive done it both ways. but i cut the wire before connecting it to the other wires, is that wrong? should i keep the connection splice then cut the wires or dose it not make a difference?

  23. I have a 98 integra with a p75 obd2a ECM. My problem is c11 and c14 have no wires going to it. What should I do? This was a gsr before I bought it and the guy made it an ls. I put a jdm engine in it and I only get a p1337. I need to get this fixed. Should I add pins to the c11 and c14? Please help

  24. Can i by pass the crank sensor on a 97 LX CIVIC IM SWAPPING A B16 A
    I HAVE PR3 OBDO AND A P2P 98 CAN I USE 98 ?

  25. Hi, I need to pass emissions next month and just realized my wire harness does NOT have the plug for the sensor, eventhough I have the sensor I cannot plug it anywhere, can I still do this trick?
    Thank you.

  26. Mario, the PR3 OBD0 ecu will not work for your swap. I highly suggest converting to OBD1 if you don’t want to touch the CKF sensor at all. If you’re use the P2P ecu and the B16A engine is OBD1 or older, then yes, you need to perform the CKF bypass trick.

  27. r0kaz,
    So no plug, but you do have the CKF wiring dangling by the crank pulley I assume? Regardless, you should still be able to perform the bypass trick since the mod is all done at the ECU plugs. Go for it and tell us what happens.

  28. Duke,
    Are you looking at ecu pinouts C11 & C14 the correct way? You should have these pin outs otherwise the car won’t even run right.

  29. John Snow,
    I believe accords have more wiring at the CKF vs. civics/integra’s do. I haven’t tried performing the CKF trick on an accord/prelude platform. I haven’t researched this so I can’t give you an answer at this time..sorry..

  30. wassup katman i did the trick on 2 cars and neither of them work i thought maybe the quick splice didnt connect to the actual wire so i tried wiring it by hand and still nothing…the car will die when i press the gas…
    and yes i cut c1 and c11, and i was thinking if there is no sensor at all why do we not the c4 or c14?

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