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Yaris intermittent starting when warm. Intermittent p0340 code


niksgee
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Hi, I am back again, this fault is driving me mad. My car has low mileage (43k). I get the engine code P0340. 

So far, Toyota put in new ECU (dont ask)

Toyota put in new cam position sensor 

I took it to an auto electrician. But the car wasnt playing up that day, no engine light and was starting first time. 

Car continued to start first time, and run well, then took to jet car wash, next day at 2am I drove to the garage to get milk, I came out, engine wouldnt start. This time was for hour and a half, I didnt think the car would start again. Engine management code p0340 again. 

When the car is about to 'go' I can feel it, the engine takes a lot longer to crank.. but it will start. If i stop and try to restart it when its like that, it wont start. But when it is behaving that doesnt happen, 3 cranks and it starts. 

I am unsure what route to go... whether to have second opinion with another auto electrician.... or to go route to have timing chain replaced (but that is £640) ouch for such an old car... I  have owned the car since 2014, so I know its history. This seems to be only real fault with the car. I dont want to pay out that much, if there is something else I have missed? 

It is driving me mad, even toyota didnt know, they didnt tell me this, and i paid for new ECU. Aragh.. So I know its NOT Ecu, Cam Position sensor. 

I am asking does it sound more likely it could be stretched timing chain? One of the symptoms I have, is car is much quieter when starting, I am not saying its really noisy as it isnt that, but i can hear what sounds like timing belt which can get louder... it is very audible right before if I switch off engine... then try to switch back on, it wont. 

I hope this makes sense.. and realise from all videos I have watched its not an easy one. Would you go with replacing the timing chain, as its not cheap, or is there something I havent thought of? 

I know some people say get rid.. but i wouldnt pass this to someone else, as it would be likely type of car as someones first car. As it has previously been reliable car, I would like to fix and keep it running for as long as possible due to low mileage. 

Thank you in advance 🙂 (I did write a post about this before) that was prior to me buying obd2 scanner, taking it to toyota who put in new cam position sensor, and then after that to auto electrician)

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On 9/16/2022 at 7:33 AM, niksgee said:

I am unsure what route to go... whether to have second opinion with another auto electrician.... or to go route to have timing chain replaced (but that is £640) ouch for such an old car... I  have owned the car since 2014, so I know its history. This seems to be only real fault with the car. I dont want to pay out that much, if there is something else I have missed? 

I would get a second opinion it cannot harm, if it was a stretched chain it would make a racket all the time but i doubt it would cause intermittent starting i have seen many videos of cars with chains that sound like they are about to break and the car still starts.

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What Does Code P0340 mean?

  • P0340 definition: Camshaft Position Sensor Circuit Malfunction
  • Issue Severity: Severe – Stop driving immediately
  • Repair Urgency: Fix this code immediately (same-day if possible) to avoid internal engine damage.
  • Diagnosis: The vehicle may be difficult to start and the driver may also experience a lack of power when driving. It is possible for more damage to occur inside the engine of the vehicle if disregarded for an extended time period. It is extremely important to repair code P0340 as soon as possible.
  • The camshaft position sensor located in the internal combustion engine monitors the position and rotational speed of the camshaft. It works hand in hand with the reluctor ring that creates a square wave voltage signal that the ECM interprets as the crankshaft position. The ECM uses this information to control ignition spark and fuel injector timing. When the trouble code P0340 is set, the ignition spark and fuel injector timing fail due to the engine not knowing when to fire these components.

https://www.fixdapp.com/blog/p0340-code/

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I wonder if there could be some wiring issue (e.g. rodents chewing on the loom) or if the VVTi is malfunctioning and not V ing the V to the expected position?

Does it sound like the chain rattles a lot when the engine is first started but goes away as oil pressure builds?

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You need to look at the wiring to the sensor in question. Error code states circuit malfunction, which means either a faulty sensor or the wiring. Jet wash, did you wash the engine too? Perhaps back to Toyota, they might not plugged in the harness properly and the wire has disconnected from vibrations, or as cyker says rodents job or from washing the engine if you did so. 👍 Don’t touch a timing chain at this low miles, age does not matter. 👍

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Is this the same car with the evap/fuel tank issue ? If it was cam chain related, it would throw other codes

to me, this sounds like a VVTi solenoid (aka oil control valve) problem/ clogged vvti filter

Assuming it's your 2002 French built car.........................

 

Oil control valve - 15330-23010

Filter - 15678-21010

seal for filter - 90430-14009

 

 

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On 9/17/2022 at 4:38 PM, Max_Headroom said:

I would get a second opinion it cannot harm, if it was a stretched chain it would make a racket all the time but i doubt it would cause intermittent starting i have seen many videos of cars with chains that sound like they are about to break and the car still starts.

I have an auto electrian who is coming on Wednesday, he seemed to know what he was talking about. Said he had the circuit wiring map for my car. Is going to put crankshaft sensor in and check all of the wiring. Quite reasonable. 2 auto electricians have said that crankshaft sensor should be done same time as the camshaft. So... thats the next thing. 

At this point have spent so much on the car might as well keep going. Hopefully one day I will get it fixed. As well as obd2 scanner bringing up the p0340 code, (esp when it was really bad and wouldnt start)... all the videos I watch on that code is identical to what is happening with my car. 

Will have to see what happens on Wednesday. 

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On 9/17/2022 at 4:41 PM, Max_Headroom said:

What Does Code P0340 mean?

  • P0340 definition: Camshaft Position Sensor Circuit Malfunction
  • Issue Severity: Severe – Stop driving immediately
  • Repair Urgency: Fix this code immediately (same-day if possible) to avoid internal engine damage.
  • Diagnosis: The vehicle may be difficult to start and the driver may also experience a lack of power when driving. It is possible for more damage to occur inside the engine of the vehicle if disregarded for an extended time period. It is extremely important to repair code P0340 as soon as possible.
  • The camshaft position sensor located in the internal combustion engine monitors the position and rotational speed of the camshaft. It works hand in hand with the reluctor ring that creates a square wave voltage signal that the ECM interprets as the crankshaft position. The ECM uses this information to control ignition spark and fuel injector timing. When the trouble code P0340 is set, the ignition spark and fuel injector timing fail due to the engine not knowing when to fire these components.

https://www.fixdapp.com/blog/p0340-code/

Thanks. Everything that I read about it, does make sense with my car and experiences I have had. It seems to be worse with heat for some reason, which could point towards electric. Otherwise why would it run perfectly sometimes and not others? I understand this code can also come up if something else isnt working properly which could throw out the camshaft... but again, when it goes well, it goes well. Kind of. It doesnt drive like a wrecked car. But when it wont start, it wont start. Always that comes with rough idle. Rough idle is only when the engine warms up... not when engine is cold, then it is quiet. 

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23 hours ago, Cyker said:

I wonder if there could be some wiring issue (e.g. rodents chewing on the loom) or if the VVTi is malfunctioning and not V ing the V to the expected position?

Does it sound like the chain rattles a lot when the engine is first started but goes away as oil pressure builds?

No, this is leading me away from the chain. As videos I had seen, say that it is noisy when starting up then quietens down with stretched chain. Mine is the opposite. Quiet starting up, but gains rough idle as the engine gets warmer. Its quiet when the engine is cold. 

Could be wiring issue, that is affected by heat? As heat is a contributing factor. Which leads me to electric again? I have an auto electrician who has wiring codes coming on wednesday. 

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22 hours ago, TonyHSD said:

You need to look at the wiring to the sensor in question. Error code states circuit malfunction, which means either a faulty sensor or the wiring. Jet wash, did you wash the engine too? Perhaps back to Toyota, they might not plugged in the harness properly and the wire has disconnected from vibrations, or as cyker says rodents job or from washing the engine if you did so. 👍 Don’t touch a timing chain at this low miles, age does not matter. 👍

Thanks, am giving toyota a wide berth on this matter. 🙂 Already they had me for a new ecu. An auto electrician is coming on Wednesday. tbh its gone on for so long am losing hope as nothing seems to fix it. But he and another auto electrician said that the crankshaft sensor needs replacing at the same time as the camshaft as they work in unison together? Kind of makes sense and have seen lots of people comment similar yt video comments. 

Am keeping my fingers crossed for wednesday. 

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Ask them to check the resistance of the vvti solenoid, if it's getting stuck or not bleeding off oil pressure, the timing will be too far advanced, and it will not start or start very poorly, especially when hot or the engine has been revved - i have seen this many times

 

also be aware there are also 2 different cam/crank timing setups on both the 1.0 and 1.3 - early ones use a 2 pin cam sensor the later ones are 3 pin

 

Remember, a code isn't the cause - it's a diagnostic aid

 

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If the vvt solenoid is sticking, how will measuring resistance identify that? Power, ground and output of can position sensor should be checked before simply replacing it, output and timing could be confirmed with an oscilloscope. If the electrician isn't going to diagnose before changing parts then he's doing no more than guessing, and the bloke down the pub could do that free of charge!

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On 9/19/2022 at 12:55 PM, flash22 said:

Ask them to check the resistance of the vvti solenoid, if it's getting stuck or not bleeding off oil pressure, the timing will be too far advanced, and it will not start or start very poorly, especially when hot or the engine has been revved - i have seen this many times

 

also be aware there are also 2 different cam/crank timing setups on both the 1.0 and 1.3 - early ones use a 2 pin cam sensor the later ones are 3 pin

 

Remember, a code isn't the cause - it's a diagnostic aid

 

Thanks he is coming this morning so I will ask him to check resistance for it. My friend was with me, knows about cars as I read this, he knows the sound of it, and has heard it not starting (happens a lot when I drive uphill to his). He said it could be that too. 

Thanks, I so hope I get some solution to this, its too low mileage and otherwise good to let go of. 

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1 hour ago, Saxmaniac said:

If the vvt solenoid is sticking, how will measuring resistance identify that? Power, ground and output of can position sensor should be checked before simply replacing it, output and timing could be confirmed with an oscilloscope. If the electrician isn't going to diagnose before changing parts then he's doing no more than guessing, and the bloke down the pub could do that free of charge!

yes he is going to check the wiring, And went to check he had the right wiring map for my car before agreeing to the job. How would you check if a vvt solenoid is sticking?

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The resistance will tell you the state of the motor/solenoid it's not conclusive but a basic test, it's only a 2 pin connector and should be in the 5.5 - 12 ohm range @ 20ºc

with the mk1 yaris you can't really command it with a scan tool - its old school testing, resistance test then a 12v test on the bench to verify movement in/out by changing polarity

lower the resistance, the higher the current draw

 

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He did old skool testing yesterday. he said it wasnt solenoid. 

Noticed when testing that it wasnt getting spark when cranking and seemed to be connected to the key being pressed forward... (hard to explain that one) electrics all checked out. New crankshaft sensor put in. 

I am wondering if it is related to ignition, poss ignition switch, with there being no spark, it being an intermittent fault, and it does seem to be affected by the key being pressed hard forward. 

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I should say that other than this random hot starting issue the car drives perfectly, like a new car really. I wish i knew more about cars, I am learning. I dont always know the right language to use to explain. 

- no spark when the engine is cranking, tested on all four 

- Seemed to be impacted with the key pressed forward

- wiring has been checked twice now, once manually and thoroughly, new ecu, camshaft and crankshaft sensor

- seems to have hot starting issue

- p0340 code switched off and didnt come back. We figured that it could have triggered that code when the car wasnt starting which is related to something else, poss ignition

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