olaboy1:
Note that the throttle body (TPS and IAC) all work together with other components that our teacher many times has referred to as sub system, some of those are MAF and MAP. So give your MAF a check.
Also check that you bought the correct part number of your entire throttle body assy, and I think you need an expert to re-program it to work with all the existing parameters stored in your ECM.

The problem you described is a complete symptom of a bad TPS, you need your vehicle's FSM to know your exact part number, if it doesn't match it will never work well even if it's same make model and year of your vehicle.

olaboy1:
Try all these 5 steps

olaboy1:
Check your engine coolant temperature sensor also, it can affect your idle speed. Remember other components apart from throttle body can cause all sort of problems whilst you keep changing throttle body.
Btw why did you change parts multiple times when you could have easily eliminated that it's not the cause of the problem at first change.


https://www.youtube.com/watch?v=wxaohKkQF3o

olaboy1:
Go back and read all your DTC's and address them one by one. If you don't have a scan tool then you need a professional to hook it up with a scan tool and you check what the trouble codes are and how to fix them.
P0123 is not throttle body but TPS circuit too high. No need to change throttle body, infact it looks like the TPS is good but the voltage coming to it is too high for some reason, maybe wire bridging together somewhere.
You need to check wire harness up to your ECM. I don't think this should be a hard fix honestly where you have a DTC to lead you to the faults
P0223 same TPS circuit too high
P1201 No 1 cylinder misfire, this one should be ignition coil or wire
P2176 throttle actuator control system idle position not learned. This one I am suspecting is a new DTC after you changed to a new throttle body, your ECM is yet to learn the new idle position compared to the old one. Fix P0123 and P0223 first and make sure they don't come back, then we know TPS does not have circuit problem again.
You can fix P2176 next by following instructions from your FSM, and then fix misfire.
So like AutoElectNG said you need your factory manual if you really want to fix these problems or you take the car to him and pay him to fix it.

dandollar1:

Thank you, bro. I have a scanner, I read those codes myself. That P1201 was a mistake I think. I never got any code related to misfire.its P2101. All the codes I have been pulling out has to do with the throttle body. And when you go through the Internet, one of the causes always point to a bad TB, bad faulty wiring and lastly, faulty ECU.

I stay on an island in rivers state where we don't have competent technicians, if not I won't be on this for up to a year now. I don't joke with the car.

If I can get recommendation of a very good auto technician in PH who is willing to come to bonny, will be very glad.

Any suggestions?

HAPPY EASTER.

olaboy1:
AutoElectNG no worries we all understand your busy schedule as an expert that you are, and trust you would make this thread the to go place for DTC's. Looking forward to having you back
Narttis try and find where your CHT sensor is and trouble shoot the wire harness connector to the sensor for voltage and resistance checks and also ECM and of course same troubleshoot on the sensor before you decide to change the sensor. You need your repair manual to do this.
Good luck

AutoElectNG:
TOYOTA AVALON 2002 FINAL COMMENTS

AutoElectNG:


This might help

http://auto.howstuffworks.com/ignition-system.htm

and this video


https://www.youtube.com/watch?v=arWoIjk6seA

J0hnTrevolt:
HELP PLEASE OOOO!
Scanned my toyota avalon 2002 model and it threw up these codes
P0300
P0301
P0303
P0305

Please wat do I do and how do I go about it.
A mechanic has been suggesting I change my 02sensor and spark plugs but I need a second opinion. The ride consumes fuel BTW.
Tnx

J0hnTrevolt:

AutoElectNG:


No Oxygen sensor code above!

But so you better understand the problem that your vehicle is having could you read this: http://www.aa1car.com/library/misfire.htm

Was any work done on the engine prior to this happening? Was the engine taken apart? Were hoses disconnected? You get the gist!

This is an ignition system related fault.

Possible issues are:

Coil Packs due for change: Electrical resistance tests can confirm or disprove this!

Ignition Wires due for change: Electrical resistance tests can confirm or disprove this!

Plugs: No electrical test for this, replace with recommended if a certain mileage has been reached.

Did you swap coils and the problem jumped cylinders?

Courtesy of troubleshootmyvehicle dot com What Is a Misfire Condition?


In the simplest of terms, a misfiring cylinder is a cylinder that's ‘dead’, because it's missing one of the 3 things it needs for the combustion process to take place. It'll be missing fuel (gasoline), or spark, or air (compression).

Where is your location? I can feel that you are at your wits end. I am so sorry that I could not provide you assistance much earlier.

Like I said I wanted to give you a detailed response not a one liner.

I want you to understand what is wrong, not just to take my word for what is wrong. And I had to attend to other issues.

If you better understand how things work, you will better appreciate the work that goes into restoring a broken system.

I'll try to see how much help I can render!

If you have questions, feel free to fire them and I will see how much help I can render from my end.

Take care.

J0hnTrevolt:

Tnx alot sir for your detailed response. I'm very grateful.
The vehicle is a direct tokunbo, the engine has not bn tampered before for over six months. I changed all spark plugs and d problem persists. many a time the car jerks/vibrates and it still consumes fuel. I can remember months back a mechanic said there was air leak or something under and I had to employ d service of a welder who welded d leak or something.
Im in the east at d moment.
I do not want trial n error mechanic on d vehicle.
Please sir I really need to know where to start cos am a novice on anything vehicle related cos I want a situation I can authoritatively tell my mechanic "this is wat is wrong and I want u to fix it"
And it also consumes more fuel jus by turning and offing the ignition. Most times I leave d engine running cos I observed wen I off and on d ignition the fuel guage always go down.
Tnx

olaboy1:
John you are having misfires and I believe your first point of call are your ignition coils. When I was troubleshooting my ignition coils, I unplugged the coils and got all those codes, and erased the codes when I was finished.

I was also told by a top tech guy in Toyota company that one bad ignition coil could cause others to have problems and throw those codes.
You will have bad gas mileage since your combustion chamber is not well fired by your ignition system. Maybe you could also eliminate a timing problem, and check that your fuel delivery system is working good like your fuel pump, fuel filter and injectors are spitting fuel properly.

If I were to fix this myself, before I start looking everywhere I will make sure the components throwing those codes are checked first before sub components, meaning I will carry out proper electrical resistance and voltage checks on all the ignition coils, then next the wires coming to the plugs, and finally ECU pins supplying voltage to the coils. If all these pass then we might be looking at other causes.

AutoElectNG:


Nice to have you again, I know you asked a lot of questions that I did not answer.

I will try to ensure that I dispose of all of them before next week runs out!

How is your ride?

Any issues?

AutoElectNG:


Where are you based?

olaboy1:
John you are having misfires and I believe your first point of call are your ignition coils. When I was troubleshooting my ignition coils, I unplugged the coils and got all those codes, and erased the codes when I was finished.

I was also told by a top tech guy in Toyota company that one bad ignition coil could cause others to have problems and throw those codes.
You will have bad gas mileage since your combustion chamber is not well fired by your ignition system. Maybe you could also eliminate a timing problem, and check that your fuel delivery system is working good like your fuel pump, fuel filter and injectors are spitting fuel properly.

If I were to fix this myself, before I start looking everywhere I will make sure the components throwing those codes are checked first before sub components, meaning I will carry out proper electrical resistance and voltage checks on all the ignition coils, then next the wires coming to the plugs, and finally ECU pins supplying voltage to the coils. If all these pass then we might be looking at other causes.

J0hnTrevolt:
Tnx alot sir for ur time I really appreciate. When the mechanic changed all the spark plugs I asked him how about d ignition coils hope they working fine and he said they were OK. I don't know if hes right or wrong tho. I read up online and most of the cause of misfire was saying bad ignition Cool like u pointed out, bad spark plugs, bad fuel injector.
Please sir if its a bad ignition Coil do I need to change all of them?
And if its a bad fuel injector can it be serviced or getting a new one. The fuel consumption is outrageous and this is still a very beat ride.
Tnx alot sir

olaboy1:


Great to have you back also, please take your time and attend to your customers also. My previous mechanic does not have the tech ability to fix my problems even something as simple as checking for vacuum leaks, so I have booked a time with a bigger workshop to diagnose and fix the problem. I have done all essential preventative servicing and still no headway my HC now 95 and CO 1.2. Even though I don't have any DTC's or misfire codes like john, it still appears on my car we still need to go John's route of Spark, Fuel and Air, and also I am suspecting a bad CAT or ignition coils, but only a professional scan tool can diagnose the actual problems without any DTC. I shall address the high CO first and also why is the CO good at 2500RPM. My ignition timing is not over advanced as it's at 10.0.

I bought a fairly used 30,000km TPS but it was super hard installing it on the throttle body and it got broken, so I had to buy another throttle body and left the TPS on it exactly how it came but I'm still getting around 30% at WOT like my old TPS. Don't know why the TPS cannot just be plug and play especially since it's not an adjustable TPS.
I will update how everything goes.

AutoElectNG:


The bolded is totally absurd to me.

It is an electrical part, either it works or it doesn't. Which is an question that electronics electricity will answer through a measurement of resistance, which is a question mathematics would help resolve through a Digital Multi-Meter, evidence that he is trying to fix the vehicle without consulting the ultimate reference guide.

Same goes for the fuel injectors! Mathematics and Electronics electricity will provide the most accurate answer, working or not!

http://www.doityourself.com/stry/how-to-test-a-fuel-injector