.:FFS TechNet : CKF Bypass Trick :.

Author_ Katman | Created_May 2006 | Last Update_Jan. 2009

CKF TRICK UPDATE - > CLICK HERE

SYNOPSIS

This article describes how to trick a U.S. OBD2a or OBD2b ecu into thinking a CKF sensor is wired in when there actually is no CKF sensor on the engine.

What is the CKF sensor?
The CKF is the Crank Fluctuation Sensor.
On all 96+ (OBD2) Honda/Acura vehicles, this sensor is integrated onto the oil pump.
(CKF images soon)

This trick is mainly aimed to help hybriders who are using a U.S. OBD2a/b ecu in their vehicle, but their motors are lacking a CKF sensor. For example, running an JDM OBD2 engine in a US 96+ vehicle but retaining the US OBD2 ecu. For those that don't know, when using a US OBD2 ecu and the CKF sensor is not wired in, the engine runs like total crap. This trick basically taps the CKF into the CKP signal.

This wire trick will save you money (around $300) and headaches!

UPDATE Jan/09
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 explained in RED within the procedures below.

PROCEDURE

Please refer to the ecu pin out page respective to your OBD2 type and take note of the CKF pin locations:
OBD2a pin out schematics
OBD2b pin out schematics
Get 4 Scotch-lock/tap splicers
Sometimes dubbed 'quick splice', these can be real life savers.
Get yourself 2 of these bad boys and a pair of pliers for the squeezing-splicing portion of the job.
Locate ECU pins

OBD2a Users:
This mod requires you to quick splice a total of 4 wires (2 wires per quick splice).
Locate the blue ecu plug "C":

Now locate pinout C1 (CKFP) and C4 (CYPP) ; using the pliers quick-splice these two wires together as shown.
THEN EITHER DEPIN C1 FROM THE ECU PLUG OR CUT IT (A FEW INCHES BACK):

Then locate pin C11 (CKFM) and C14 (CYPM) and quick-splice these two wires together as shown.
THEN EITHER DEPIN C11 FROM THE ECU PLUG OR COMPLETELY CUT IT (A FEW INCHES BACK):

The reason for de-pinning or cutting C1 and C11 is to prevent CEL code 9 (CYP) from happening. This happens because sharing the signal at two locations creates a conflict.

That's it!
Your finished OBD2a quick-splice job should look something like this:

OBD2b Users:
This mod requires you to quick splice a total of 4 wires (2 wires per quick splice).
Locate the blue ecu plug "C":

Now locate pinout C22 (CKFP) and C29 (CYPP) ; using the pliers quick-splice these two wires together as shown.
THEN EITHER DEPIN C22 FROM THE ECU PLUG OR COMPLETELY CUT IT (A FEW INCHES AWAY FROM THE PLUG)

Then locate pin C30 (CYPM) and C31 (CKFM); quick-splice these two wires together as shown.
THEN EITHER DEPIN C31 FROM THE ECU PLUG OR COMPLETELY CUT IT (A FEW INCHES AWAY FROM THE PLUG)

The reason for depinning or cutting C22 and C31 is to prevent CEL code 9 (CYP) from happening. This happens because sharing the signal at two locations creates a conflict.

That's it!
Your finished OBD2b quick-splice job should look something like this: