DIY PGMFI Diagnostics - Code 4 CKP
Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!
No part of this DIY is to be reproduced with out acknowledgment of the site and author it came from, ie me and ozhonda.com. Do not rip parts off and claim them as your own.
CKP Sensor "Crank Position Sensor" also known as RPM Sensor. The CKP sensor is commonly located on the side of the head, inside the Distributor. Not to be confused with the TDC or CYP sensor that is also located in the distributor, or in its own housing driven by the exhaust camshaft. On V6 Engines the CKP can be found behind the camshaft pulley. The CKP is a magnetic pulse generator type of sensor. The ECU monitors the CKP to determine crankshaft position and RPM and is the primary sensor for the ignition system.
Below is a picture of an CKP CYP TDC sensor in a B16A2 Distributor. The yellow arrow is pointing to the CKP magnetic pickup and the pulsar
http://ecu-man.com/diy/pgmfi/ckp/PGMFI-ckp-sens.jpg
Aim:
Diagnose code 4.
http://ecu-man.com/diy/pgmfi/mil/pgmfi-code-4.gif
Required:
Basic Testing
- Digital Multi Meter
- Tachometer ( vehicle tacho can be used )
- paper clip
Advanced Testing
- all the above
- oscilloscope or wave form viewer
Symptoms
For a faulty CKP sensor to trigger code 4, you will more than likely get the engine light come on and the car will go into limp mode, Limp mode is a preset fuel and ignition map running on a backup processor in the ECU. Limited to about 3500rpm and a rich mixture to protect the engine. The engine will run, but not the best. Common cause for code 4 is a damaged CKP from distributor bearing failure or open circuit in the sensor or wiring back to the ECU.
Basic Test
- Perform a Visual inspection and make sure the CKP sensor is connected, lisen for metallic sounds from the distributor. Save yourself allot of time, If you have a very noisy distributor with lots of grinding metallic sounds, replace your distributor.
CKP Sensor Pin out Picture
OBDO
http://ecu-man.com/diy/pgmfi/ckp/PGM...O-EF8-conn.JPG
OBDI
http://ecu-man.com/diy/pgmfi/ckp/PGMFI-OBD1-conn.JPG
wire side of connector
( note, unfortunately CKP sensors come in a variety of different connectors for different types for Honda's. In this DIY, I have just covered the basic all in one distributor. If you have a 4 wire distributor, Legend ect, reply to this thread and I’m sure some one will be able to help. )
**** Resistance Test **** Set the multi meter to ohms ( 2k scale )
Unplug the CKP sensor, connect your Red multi meter lead to the CKPP. Connect your Black multi meter lead to the CKPG.
CKPP
OBDO = Pin 2
OBDI = Pin 5
OBDII = Pin 5
CKPG
OBDO = Pin 1
OBDI = Pin 6
OBDII = Pin 6
their are two types of sensors.
350ohm to 750ohm ( most Honda's are 350ohm to 750ohm)
or
700ohm to 1300 ohm
If your CKP is not with in spec replace it ( or the distributor ). To be safe, consult the workshop manual for the actual specs for you CKP.
**** Voltage Test ****
Set your multi meter to AC Volts ( 20v scale )
Step 1
Check the CKP sensor for its output Voltage to the ECU, Connect the Black Lead from your multi meter to the chassis for a good ground. Back probe* the CKPP ( Crankshaft position Sensor Power) with the Red lead while the sensor is connected.
OBDO = Pin 2
OBDI = Pin 5
OBDII = Pin 5
KOER* at idle ( 800RPM ) you should get about 2.5 to 3vac
KOER* at 2500RPM you should get about 7.5 to 8vac
You can also test the CKP signal at the ECU connectors
OBDO = C1
OBDI = B15
OBDIIa = C2
OBDIIb = C8
If you do not get a signal, replace the CKP ( distributor )
**** Frequency Test ****
Set your multi meter to Hz scale
Step 1
Check the CKP sensor for its output frequency to the ECU, Connect the Black Lead from your multi meter to the chassis for a good ground. Back probe* the CKPP ( Crankshaft position Sensor Power) with the Red lead while the sensor is connected.
OBDO = Pin 2
OBDI = Pin 5
OBDII = Pin 5
KOER* at idle ( 800RPM ) you should get about 160khz
KOER* at 2500RPM you should get about 490khz
You can also test the CKP signal at the ECU connectors
OBDO = C1
OBDI = B15
OBDIIa = C2
OBDIIb = C8
If you do not get a signal, replace the CKP ( distributor )
**** Continuity Test ****
Set your multi meter to continuity. This setting is mostly a picture if a sound .))) when you touch the Red and Black leads together on your meter it should beep.
STEP 1
make sure the Ignition is off and unplug the CKP Connector and the ECU Connectors for this test
Continuity test between CKPP and ECU, Connect your Red multi meter lead on the CKPP, Back probe* the Black multi meter lead on the ECU Pin below that suits your car.
OBDO = C1
OBDI = B15
OBDIIa = C2
OBDIIb = C8
your multi meter should beep and read short or 000.0ohms. Place the black multi meter lead on a good ground source. You should not get beeping, this is testing for short to ground.
STEP 2
make sure the Ignition is off and unplug the CKP Connector and the ECU Connectors for this test
Continuity test between CKPG and ECU, Connect your Red multi meter lead on the CKPG, Back probe* the Black multi meter lead on the ECU Pin below that suits your car.
OBDO = C2
OBDI = B16
OBDIIa = C12
OBDIIb = C9
your multi meter should beep and read short or 000.0ohms. Place the black multi meter lead on a good ground source. You should not get beeping, this is testing for short to ground.
Advanced Test
You may pass all the above test with no problems at all. Unfortunately this does not mean all is well. You can have a sub code to the code.
example code 4 -1
code 4 is CKP
sub code 1 ( for example, ) is noisy CKP
You will not get sub codes from the SCS and MIL, you need the HDM or PGMFI Tester from the DLC port.
So in this advanced test, we are going to test the CKP with an Oscilloscope or Waveform Viewer to look at the signal generated from the CKP close up. The aim is to get a nice clean sine wave with out any glitches or drop outs.
Common causes of noisy sensors are rebuilt distributors. Once the bearing has failed and the pulsar has gone to town on the magnetic pickup and has damaged the pulsar and pickup assembly. Just changing the bearing in a dizzy rebuild sometimes doesn’t cut it. Also cracks in the sensor housing is a bad thing.
Test Time
Connect the Black Lead from your waveform viewer to the chassis for a good ground. Back probe* the CKPP ( Crankshaft position Sensor Power) with the Red lead while the sensor is connected.
OBDO = Pin 2
OBDI = Pin 5
OBDII = Pin 5
KOER, you should get a pattern that looks abit like the pattern in the pic below.
http://ecu-man.com/diy/pgmfi/ckp/PGMFI-ckp-sinewave.jpg
you should not get a pattern with glitches or fuzz in the sinewave like in the pic below. if you do replace the sensor/distributor
http://ecu-man.com/diy/pgmfi/ckp/PGM...adsinewave.jpg
* Notes
KOEO = Key On Engine Off
KOER = Key On Engine Running
Back probe the sensor, use a paperclip and push it into the connector then touch/clip your multi meter lead to the paper clip
Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!
