DIY PGMFI Diagnostics - Code 23 Knock Sensor

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.




KS " Knock Sensor ". The Knock Sensor is commonly located on the back of the block under the intake manifold. The Knock Sensor produces an AC voltage when engine knocking is detected. As the engine knocking increases, the KS output voltage increases. The ECU monitors the KS to retard ignition timing when engine knock is detected.




Aim:

Diagnose code 23.

http://ecu-man.com/diy/pgmfi/mil/pgmfi-code-23.gif



Required:

Basic Testing

- Digital Multi Meter
- Oscilloscope or waveform viewer
- paper clip


Symptoms

A faulty KS Sensor will trigger code 23. The Engine light will come on and code 23 will be registered in ECU memory. An open circuit in the KS circuit will also cause problems.



Basic Test


- Perform a Visual inspection and make sure the KS is Connected.


KS Pin out Picture



http://ecu-man.com/diy/pgmfi/ks/PGMFI-ks-pin.jpg

wire side of connector





**** Continuity Test ****


STEP 1

make sure the Ignition is off and unplug the KS Connector and the ECU Connectors for this test

Continuity test between KS Pin 1 and ECU, Connect your Red multi meter lead on the KS Pin 1, Back probe* the Black multi meter lead on the ECU Pin bellow that suits your car.




OBDO = B19
OBDI = C3
OBDIIa = D6
OBDIIb = C3




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.



**** Voltage Test ****




Set your Oscilloscope or waveform viewer to DC Volts ( Y ) ( +2v and -2v scale ) @ ( X ) 1 or 2 second time shift


Step 1


Back probe* the Red multi meter lead on the KS Pin 1, connect the black multi meter lead to a known good ground.


tap on the engine block near the knock sensor ( don’t smash it ) and you should get a reading. bellow is an example of a pattern generated by the KS.


http://ecu-man.com/diy/pgmfi/ks/PGMFI-ks-test.JPG


if you do not get a reading replace the Knock Sensor.


* Notes

KOEO = Key On Engine Off

KOER = Key On Engine Running

Backprobe the sensor, use a paperclip and push it into the connector then touch/clip your multimeter 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!