Looking for ecm pinout LS430 for knock sensor hack
Racer
Joined: Apr 2002
Posts: 1,667
Likes: 210
From: Someplace in CT
Here's some info on P0174 and P0171. The codes indicate that your engine is running too lean. Please take a look at Post #6 of this thread, I suspect the symptom may very well be the result of re-routing the one knock sensor to both signal inputs to the ECM - your ECM is adjusting the air-to-fuel ratio based on the wrong "knock" signal.
As shown in the illustration below, the LS430 engine fires in the following order 1-8-4-3-6-5-7-2, at 45 degree separation. The knock sensors are like microphones that listens for ignitions of piston "3" and piston "6", that are 45 degree apart. The ECM compares crankshaft position vs. the "knock" and make necessary adjustments to timing and air-to-fuel ratio to remedy abnormality. Your ECM is having difficulty to line up the crankshaft position with the 2 identical knocks that are supposed to be 45 degree apart.
As shown in the illustration below, the LS430 engine fires in the following order 1-8-4-3-6-5-7-2, at 45 degree separation. The knock sensors are like microphones that listens for ignitions of piston "3" and piston "6", that are 45 degree apart. The ECM compares crankshaft position vs. the "knock" and make necessary adjustments to timing and air-to-fuel ratio to remedy abnormality. Your ECM is having difficulty to line up the crankshaft position with the 2 identical knocks that are supposed to be 45 degree apart.
I noticed that it could be a vacuum hose causing this, as we put the car back together we kind of rushed it, I should double check it before going any deeper on this.
Will these codes coming up (and seeing that it could be adding more air or fuel to the mix), will this cause any perm damage to the car by driving it ? It might be a few days before I can get under the hood.
As for driving the car, the car drives perfect, smooth and full of power.... almost as nice as when it was newer... I just dont want to damage it more by driving it (still need to get to work)
Lexus Champion
Joined: Mar 2011
Posts: 2,186
Likes: 728
From: Texas
Typically, DTC's do not reset automatically (you will have to clear it manually), so reconnecting the knock sensor will not clear the DTC. However, it will likely to prevent the DTC's to return after you reset them manually.
As you probably already know, the 4-cycle engine operates thru 4 stages: Intake stroke, Compression stroke, Power stroke, and Exhaust stroke. During the Intake stroke, the piston travels downward to draw in fuel/air mixture; then the piston travels upward to compress the fuel mixture in the Compression stroke; at the top of the stroke, the spark plug fires and the explosion pushes the piston downward during the Power stroke; then finally, the piston travels upward to push out the exhaust gas. A "rich" mixture can cause early ignition (before the spark plug fires) - this is also known as "dieseling". In other words, a "rich" fuel mixture will ignite while the piston is on its way up which will apply more force on the piston top. To make matters worse, the Power stroke is supposed to occur when the piston passes the TDC and starting on its way down. Early ignition catches the piston on its way up, essentially slowing its travel and works against the rotation of the crankshaft. On the other hand, "Lean" mixture will not ignite until the spark plug fires and because it's lean, less power is produced.
I don't think running your car lean will cause damage, at least not for a short term (a few weeks or even months). You may experience lower MPG performance. The troubleshooting steps for P0171 and P0174 mention vacuum hose leakage and a few other items to check - I'd start with those items. Meanwhile I would clear the DTC and see if they return.
As you probably already know, the 4-cycle engine operates thru 4 stages: Intake stroke, Compression stroke, Power stroke, and Exhaust stroke. During the Intake stroke, the piston travels downward to draw in fuel/air mixture; then the piston travels upward to compress the fuel mixture in the Compression stroke; at the top of the stroke, the spark plug fires and the explosion pushes the piston downward during the Power stroke; then finally, the piston travels upward to push out the exhaust gas. A "rich" mixture can cause early ignition (before the spark plug fires) - this is also known as "dieseling". In other words, a "rich" fuel mixture will ignite while the piston is on its way up which will apply more force on the piston top. To make matters worse, the Power stroke is supposed to occur when the piston passes the TDC and starting on its way down. Early ignition catches the piston on its way up, essentially slowing its travel and works against the rotation of the crankshaft. On the other hand, "Lean" mixture will not ignite until the spark plug fires and because it's lean, less power is produced.
I don't think running your car lean will cause damage, at least not for a short term (a few weeks or even months). You may experience lower MPG performance. The troubleshooting steps for P0171 and P0174 mention vacuum hose leakage and a few other items to check - I'd start with those items. Meanwhile I would clear the DTC and see if they return.
Last edited by rkw77080; Oct 28, 2016 at 11:42 AM.
Racer
Joined: Apr 2002
Posts: 1,667
Likes: 210
From: Someplace in CT
I don't think running your car lean will cause damage, at least not for a short term (a few weeks or even months). You may experience lower MPG performance. The troubleshooting steps for P0171 and P0174 mention vacuum hose leakage and a few other items to check - I'd start with those items. Meanwhile I would clear the DTC and see if they return.
I have been reading about the Symtoms of the P0174 and P0171 codes and I am getting the oppsite of what they claim (big performance hits).
I did clear the DTC after doing the hack and those codes showed up, after driving for about 100 miles, I reset the codes and they came back. I will go and disconnect and re-connect all the vacuum hoses, then try again. This is very possable that when we put the hoses back on, there might of been one or 2 that MIGHT be a little lose.
Thanks again for your advice, I hope it IS a lose hose, I hope I dont have to revierse this hack for now, as the car runs perfect...
Pole Position
Joined: Oct 2016
Posts: 306
Likes: 13
From: Auckland
Old thread and all that but I'm deep down the rabbit hole doing knock sensors and a starter motor, and trying to find the pinouts for the knock sensors wasn't easy. I had 2 codes relating to knock sensor 2 and an input signal fault, so I've replaced both sensors but now I can probe both the wires back to the plug to check for continuity. I hope my wiring is still sound, I'd rather not have to run new wires back to the ECU. I already have to fix wiring on a coil pack plug and the temp sensor plug.
Driver School Candidate
Joined: Aug 2018
Posts: 1
Likes: 0
From: Ca
Knock hack
Hi, can u send me a text pic of the knock hack.
thanks
760 799 0438
thanks
760 799 0438
I'm trying to perform the bank 1 knock sensor hack to rid myself of code P0325. The hack involves connecting the good signal from the bank 2 knock sensor to the bank 1 wire as it goes into the ecm while leaving the bank 1 sensor disconnected via a cut wire.
I have seen a similar hack performed on the clublexus gs forum.
Has anyone done this? Any ideas on where to find the pinout on the ecm so I can perform this? Any other ideas or thoughts?
Thanks
I have seen a similar hack performed on the clublexus gs forum.
Has anyone done this? Any ideas on where to find the pinout on the ecm so I can perform this? Any other ideas or thoughts?
Thanks
Driver School Candidate
Joined: May 2019
Posts: 3
Likes: 0
From: CA
If anyone wants to do this please send a phone number and I'll text a pic of the splice. Its not that the splicing is difficult, buy knowing what wires to splice was the biggest gamble. I found the information on another forum and followed the lead of quite a few 3UZ folks dealing with some old, hard and broken wiring.
Alex - 1 (949) 230-6775
Driver School Candidate
Joined: May 2020
Posts: 1
Likes: 0
From: CA
knock sensor by pass
That is exactly what I did. It was a little gamble, but it seems to have paid off. I simply spliced knock sensor 1 and 2 together. Then I cut the "bad" sensor wire going back to the sensor. No check engine lights. Runs just like it should and as easy as it was to execute, wish I would have done it sooner.
The hardest part for me was disassembling the glove box to get to the abs? module that I thought was the ecu. The ecu couldn't be easier to get to. Folks with the similar GS430 are a little more open to experimenting and trouble shooting in this workaround. All I can say now is so far so good.
The hardest part for me was disassembling the glove box to get to the abs? module that I thought was the ecu. The ecu couldn't be easier to get to. Folks with the similar GS430 are a little more open to experimenting and trouble shooting in this workaround. All I can say now is so far so good.
Interested in how to do what you did to knock sensor bypass
Advanced
Joined: May 2001
Posts: 650
Likes: 7
I'm trying to perform the bank 1 knock sensor hack to rid myself of code P0325. The hack involves connecting the good signal from the bank 2 knock sensor to the bank 1 wire as it goes into the ecm while leaving the bank 1 sensor disconnected via a cut wire.
I have seen a similar hack performed on the clublexus gs forum.
Has anyone done this? Any ideas on where to find the pinout on the ecm so I can perform this? Any other ideas or thoughts?
Thanks
I have seen a similar hack performed on the clublexus gs forum.
Has anyone done this? Any ideas on where to find the pinout on the ecm so I can perform this? Any other ideas or thoughts?
Thanks
Driver
Joined: May 2018
Posts: 82
Likes: 7
From: NC
2nd gear
Joined: May 2024
Posts: 2
Likes: 0
Picture
If anyone wants to do this please send a phone number and I'll text a pic of the splice. Its not that the splicing is difficult, buy knowing what wires to splice was the biggest gamble. I found the information on another forum and followed the lead of quite a few 3UZ folks dealing with some old, hard and broken wiring.
hey revrun can you please send a picture of the splice to me @ 6502706128 asap
1st Gear
Joined: May 2018
Posts: 1
Likes: 0
From: fl
If anyone wants to do this please send a phone number and I'll text a pic of the splice. Its not that the splicing is difficult, buy knowing what wires to splice was the biggest gamble. I found the information on another forum and followed the lead of quite a few 3UZ folks dealing with some old, hard and broken wiring.
I have a 2002 SC430 that keeps throwing P0325. I have replace both knock sensors with OEM and the brittle wires and connectors about 6” back from the sensors.
strangely, the code will show, engine runs like crap, I turn the car off then restart. While the CEL stays on, it will run normal. Then after driving for a while, the light goes off.
then a day or two later it does it all over again
Andrew
407.399.0292
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