Toyota Repair: Vvt-i or ECM thats a problem, fe engine, ocv

Question
Hello!

Best wishes from Finland.
I just want to ask from you about getting DTC 1349 from my Toyota Avensis (build year 2002 and with 3zz-fe engine, (it’s like 1zz-fe but is 1,6 ltr petrol engine).  My local shop want to sell to me  the new Vvt-i actuator, but I am not sure if problem is there at all... I think that there are some problems in ECM. Can it be so?

These are symptoms:

Only DTC 1349 occurs, nothing else DTC at all.   DTC comes occasionally, but it occurs.  Check engine light comes and goes. The car seems to be lazy when climbing hills or if need some extra power to overtaking  in highway… the check engine light comes sometimes, sometimes it will not, but the car is lazy.

When I hooked Flukes Scopemeter  behind ECM  (to OCV+ and OCV-   =OCV is Oil Conrol Valve))  and go test-drive, I found something strange:

At first when I start to drive everything’s is right. ECM seems to regulate the oil control valve, the OCV gets changing voltages from ECM.
About after 20 kilometres later, something strange happends. The voltage from ECM drops about  to 0,87 volts and remains there. It doesn’t change even if I give more gas or loose it, or if I take other gear…   The engine load varies a lot, but the regulation voltage not.  I have noticed that only way to get voltages  “living” again, is to slow down speed  almost  to 0 km/h, then ECM seems to wake. And works again until the voltage again drops and remain to 0,87 V. This result I get when I use fluke as trend plotter. Engine looks to be in Vvt-i area (400-4000 RPM)

When I zoom closer the moment when the voltages  “freeze”, there is about 20-30 sec. long time when the ECM seems to come crazy. The voltage goes up to 8 volts and then comes down  to 0,87 volts…  many time s in sec.  It takes about 12 msec  from  top to down  and again to top.  The waveform which trendplotter gives to me looks like oscillografs in some observatory when  they measures  the earthquake.  After that just nothing movement… the voltage is steady 0,87 volts.  

When I looked closer the waveform which I get from ECM, it seems to be like normal. The pulse width becomes longer when I give fore gas, that’s ok I understand. The rise time is normal etc.  Even in times which I told in last chapter  when the voltages is moving quickly, the waveforms shape seems to be normal. Pulse width is only which varies from long to short.

And now we become to questions which I am thinking…. Does this like to be normal behaving to ECM ?   Does the ECM try to move valve timing about 20-30 sec and then is giving up... and  gives  after that only low voltages to OCV ?  Is there some logically or something else problems inside the ECM? Some problems inside the ECM  which becomes actually after I have drived about 20 kilometres.  

Or is the main problem in VVT-I actuator which is jamming. And I must to change it first.   I have already checked that engine oil is clean and the little filter behind bolt is clean (filter which sometimes is clogged I have read from some websites).  The Oil Control Valve seems to be in condition, because the engine stalls, if I give battery voltages to it (accordingly factory repair manual).

The ECM seems to get good grounds and voltages, because the rise time and the waveforms shape is “nice to look”.  

What you are thinking, where the problem is?  Somehow as a family man, I just don’t want to give up and drive the car in some garage which gives me bill… a big bill.  They will first change new Vvti- actuator which costs about 350 USD  just parts, excluding work costs.

If  the main problem is ECM , then I must  pay  The Vvt-i  actuator and then ECM, and then …  and give a lot money to garage…. I can change actuator myself if there is the problem (I am car mechanic, but I worked with commercial vehicles.  

Tell se what you are thinking, do you have meet Vvt-i problems ?  My has 3 zz-fe engine, which also likes to drink oil- today 4,3 litres /10 000 kilometres. It seems to have problems with piston oil rings….  if it would have less kilometres Toyota might change the short engine, but unfortunately not in my case….  so there is many places to place money in my car…

The best regards

Juha  

Answer
In most cases this trouble code can be eliminated by replacing the camshaft gear that has the VVT-i controller. Yes , I have seen this problem a few times and replacing the gear solves the problem, I have never had to replace an ECM because of this code.