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2002 lexus is 300 AT
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Discussion Starter · #1 ·
Hey guys me again. I'm having an issue I can't seem to track down the root causeand getting some major codes. P0300 random cylinder misfire, P1349 (valve timing system malfunction), p1346(vvt bank 1) and p1120 (accelerator position sensor circut) and all cylinders misfire. I've replaced the vvti solenoid and filter and the pedal position sensor. Replaced pedal Position sensor connector and tps connector (broke them in previous endeavors). Checked all the circuits to make sure all were receiving power. I have also rebuilt the vvti gear replace cam and crank seals timing belt is new and seems to be still in good timing. Car will start and run. Was going to check to see if they were communicating to the ecm/pcm etc... and this is what I found! Please help!!!!
Symptoms: have to push the pedal to the floor to get any response. Rough idle. Trac off light blinking.. engine light solid.high engine idle only when in park around 1200 to 1500 rpm drops to 800 when in any other gear.
Office equipment Bumper Automotive exterior Grille Gas
 

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It’s possible the capacitors are leaking inside the ecu board. I’d take it apart to see. Careful of static shock although this one might be passed saving.

Was it securely closed with the cover on before you took it apart?
Was the APPS you installed new?
Do you have access to a bidirectional scan tool?
 

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Is the fluid oil? I’ve heard of incidents where an oil pressure sensor or VVTi solenoid allowed oil thru the sensor and up the wire to the ecu.
 

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2002 lexus is 300 AT
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Discussion Starter · #4 ·
The cover was securely on, the ecu is original. Took it apart and it looks pristine no breakage corrosion or anything like that. I replace the solenoid with a brand new one oem I also read on several forums and threads that the oil could leak from the solenoid after I replaced it so I am unsure if thats what was cause the issue. And the APPS is also new oem as well. I reset the comp but removing the + and - terminals from the battery. I tried programing the new apps both before and after I disconnected the battery. Im just at a loss and I can't afford to pay someone or keep buying parts to figure put what's wrong. I read that there also could be an issue with the ecm communication with the pcm but I don't have the tools to diagnose that.
 

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2002 lexus is 300 AT
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Discussion Starter · #5 ·
It’s possible the capacitors are leaking inside the ecu board. I’d take it apart to see. Careful of static shock although this one might be passed saving.

Was it securely closed with the cover on before you took it apart?
Was the APPS you installed new?
Do you have access to a bidirectional scan tool?
I do not have access to the scan tool just a volt meter to check for power. I lost my job due to now being able to figure out my transportation 😞.
 

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It’s gonna be hard to diagnose this without a scanner. Perhaps borrow one from Autozone? You want to see APPS values, (you can see that with the volt meter by back probing) and with a bidirectional one you could even command the vvti on and off. Seeing as how these are circuit codes I’m guessing it’s gonna be a common cause. Bad ground or bad connection.
Does your meter have a resistance check function?
 

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At the APPS connector pin
1 is VP2
2 is VPA
3 is ground
4 is 5v supply.
VPA Signal with throttle closed .25-.9v. Fully open 3.2v-4.8v.
VP2 closed 1.8-2.7v. Open 4.7-5.1v.
Make these checks before spending any more money.
 

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I do not have access to the scan tool just a volt meter to check for power. I lost my job due to now being able to figure out my transportation 😞.
Super cheap. I assume you have a smart phone. There are several free apps.
 

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You can also use the jumper method to see any of the more basic codes, have a search. You bridge 2 of the pins on the OBD port and it will flash the codes on the engine check light.
 
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