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Discussion Starter · #1 ·
I have had my Celica for 3 years and done lots to it and used these forums many times to solve my issues without posting but I am stumped with this one and could really use the help, If you have any insight with this wiring issue I'm having I would greatly appreciate you sharing anything you think might help/ be the cause

This might be lengthy but I have had a complicated history with this issue, I have tried everything besides just ripping my wiring harness apart and I was wondering if anyone knew what might be wrong before I irreparably tear into my mostly stock wiring harness.

DISCLAIMER: Although this issue is related to an ecu swap I had it working for nearly 2 years before having these issues /// TLDR and Questions Below ///

Background Information
2002 Toyota Celica GTS w/ 6 speed
2001 ecu and single knock sensor swap w/ single pin connector/pigtail with shielding.
03 Matrix XRS 2zz Installed July 24, 2022
05 Vibe GT C60 Installed April 2022

The Story:
So I have had my Celica for 3+ years and as a 2002 GTS owner I decided to swap to an 2001 ecu for lower lift engagement and 8400 rpm fuel cut. After having 01 ecu swap working for 2 years, wire got caught between starter and block after trans swap and after rough terrain CEL and damaged pigtail, Replaced Knock sensor pigtail and knock sensor and still getting inconsistent P0325 Knock sensor circuit malfunction causing limp mode.

Original Install Order of Events

1.) Installed 2001 Ecu and Single wire knock sensor (Import Direct Sensor #17-1543) Used a single wire connector from a v6 pigtail obtained off amazon/ebay complete with shielding wire.

2.) Person I bought ecu from incorrectly said White wire (Pin 28/EKNK/2002 Harness/ECU only) was the knock sensor signal wire and after removing the intake many times I simply switched the White wire (Pin 28/EKNK/2002 Harness/ECU only)to connect to the Black wire (Pin 27/KNK/Both 01/02 Ecu and Harness) by ecu connector because the Black wire is the correct signal wire for knock sensor.

3.)So After using the White wire (Pin 28/EKNK/2002 Harness/ECU only) all the way down to the pigtail and connecting white to white for signal and black to black for shielding and simply cutting and using a crimp connector White wire (Pin 28/EKNK/2002 Harness/ECU only) to Black wire (Pin 27/KNK/Both 01/02 Ecu and Harness) to correct being told wrong signal wire cut white wire by ecu and crimp connector to the black wire for knock sensor signal wire to ecu plug.

4.) After Swapping Knock Sensor/Sensor Harness and ECU I had it working from April 2020 to April 2022. After Swapping in my latest C60 the Knock Sensor Harness got stuck between the block and starter (extra long because obtained from v6 single wire harness) and when driving over rough terrain I got a CEL and found the knock sensor pigtail damaged and replaced it. After just replacing the harness I still got inconsistent CEL often being set off after hitting lift or high rpm

5.) Fast forward to July 2022, Replaced the Knock Sensor with a brand new one (Same exact part that worked before). Seemed to be fixed no issues for ~ 4 days

6.) Replaced Knock Sensor 7/8/22 and then Spun cyl 4 rod bearing 7/12/22. Got a new 03 xrs 2zz Put in 7/24/22 and thought the knock sensor issue was fixed and got a CEL. New Engine, Fixed my 6th gear on c60, and Replaced wheel bearings but can't get my knock sensor check engine light to go away, Replaced Knock Sensor pigtail used extra shielding and grounded to ground by hard water pipe/block. still no luck.

Details on the wiring, So from the sensor I used a single wire harness that came off a v6 knock sensor harness so it has shielding and has worked for me in the past, soldered the pigtail to main harness and added extra shielding and also grounded shielding to the ground by the hard water pipe by the knock sensor. Main harness I used the EKNK white wire for the knock sensor signal wire because I was told the wrong pin and swapped them by the ecu connector and worked like that for 2 years with the black wire used for shielding sensor side and not connected to ecu with white wire crimped to black wire ecu side.

NOTE: Tried connecting the EKNK to outside body ground and did not change symptoms. Removed added ground

TLDR: Possible wiring issue with knock sensor circuit, consistent P0325/Limp mode even after new Knock Sensor/Pigtail.

Questions:

Q1.) When going from 2 wires to 1 for knock sensor what do you do with EKNK only present on 02 ecu and harness?
(Mine is currently cut by ecu and then grounded near the knock sensor.

Q2.) Could the spun bearing on my first engine ruin the knock sensor causing it not to work properly after putting new engine in, also do knock sensors fail completely or partly work and then die fully?

Q3.) Could the EKNK (2nd wire from 02 knock sensor/harness) cause circuit issues by leaving it cut and exposed by ecu and then grounding the shielding to the block by hard water pipe?

Q4.) Should I buy another $70 Knock Sensor before tearing into my wiring harness due to the engine failure that could've broken the sensor?

Q5.) Most effective way to find short in the knock sensor circuit? Already used continuity test on my multimeter between Knock sensor signal wire and shielding wire and no shorts while wiggling and unplugged from ecu. Also tested voltage on knock sensor pin while tapping intake and noticed slight bump in voltage as I tapped around.

Thanks, if you're looking for more info/pictures request on here or pictures are available as highlights on my instagram @cecilia.2zz
 

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Electromagnetic Wave :-h
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Changing a 2002 ECU to a 2001 using a 2002 harness, you remove the White wire from pin 28 & move the pink PS oil pressure switch from pin 30 to pin 28 on the ECU.

Both the '01 single wire & the '02 dual wire knock cables are shielded. You can ground the unused disconnected wire to prevent extraneous electrical noise from entering the KNK circuit.

So, if I read it right, you moved White to pin 27. If so, Pink is moved to pin 28 and Black has no connection and can be grounded.

If the shielded cabling was damaged at all, make sure there are no shorts to the shielding.
 

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Discussion Starter · #3 ·
Changing a 2002 ECU to a 2001 using a 2002 harness, you remove the White wire from pin 28 & move the pink PS oil pressure switch from pin 30 to pin 28 on the ECU.

Both the '01 single wire & the '02 dual wire knock cables are shielded. You can ground the unused disconnected wire to prevent extraneous electrical noise from entering the KNK circuit.

So, if I read it right, you moved White to pin 27. If so, Pink is moved to pin 28 and Black has no connection and can be grounded.

If the shielded cabling was damaged at all, make sure there are no shorts to the shielding.
Thanks for the reply. I had pin 28 the black wire grounded to bolt on the smaller fuse box near drivers side headlight and it didn't seem to make a difference. Also what is the best way to find a short? The Toyota service manual said it's unlikely the short in the middle of the harness so id like to find it without completely tearing apart my harness. Where would be the best place to ground the black wire?, I even tried just connecting it to the rest of the shielding near the ecu connectors. Thanks 2way, you have no idea how much you've helped, I always see your replies on threads I'm looking through when troubleshooting.
 

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Electromagnetic Wave :-h
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Grounding Black can be anywhere convenient. BUT, it has to be removed from pin 28. The pink wire on pin 30 should be moved to 28 with an '01 ECU.

Finding short.... disconnect from ECU, use an ohmmeter between White and Ground. Flex/move the shielded cable along its length. Many ohmmeters have a tone on continuity. So, that makes it a bit easier.
 

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Discussion Starter · #5 ·
Grounding Black can be anywhere convenient. BUT, it has to be removed from pin 28. The pink wire on pin 30 should be moved to 28 with an '01 ECU.

Finding short.... disconnect from ECU, use an ohmmeter between White and Ground. Flex/move the shielded cable along its length. Many ohmmeters have a tone on continuity. So, that makes it a bit easier.
Yeah for the 2 years it was working it had pin 28 cut with the black wire loose in the ecu box. I already tried the tone continuity thing up by the ecu/intake, I'll just have to be more through and take off the intake manifold. I did do a voltage test on the knock sensor and it did respond to hitting the intake/block with my rachet. Thanks for the help
 

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Electromagnetic Wave :-h
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If memory serves me, while the knock sensor is AC, you may find that it rides on +5V DC on an '01.
 
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