Error P0134, lean at idle, no power at drive

Just returned from the garage. I checked the voltage across the heater (after final connector so the real voltage that reaches the heater) and it looks like a PWM signal from 0V till battery voltage (see the attachment). Is it good? I thought that it is stable 12V rather than pulse.Than I checked the O2 sensor voltage (before the final connection so from the side of ECU). At the begining of idling it fluctuates, than it stabilized to reach about 100mV when engine coolant reaches 70-75deg. Than the oscillations can be observed ONLY if I accelerate to 2k RPM or more.Any ideas what to check?

I have never measured the the heater circuit, but it seems that it is likely to be PWM, see the following article

www.picoauto.com/library/automotive-guid...irconia-with-heater/

According to the article, the ECU controls the power to the heating element, but I don't fully uinbderstand what it measures, is it current and realises when the O2 sensor is warm or does it measure [exhaust gas] temperature?

It makes sense to control the heater element, running it when it is not needed would only shorten the life. Anyway your waveforms could be correct.

The article does mention something else, is your engine running in 'Closed Loop' (using O2 sensor) or 'Open Loop', just add the fuel status object to your Torque screen.

At idle and under normal driving, you should be in closed loop. When accelerating [hard] or when engine breaking you go in to open loop as the O2 sensor is not a reliable way of setting the mixture under these two conditions.

Where next, well I would check the plugs to see if it is running rich or lean, that might help determine the next step. If it is running lean, this confirms the Lambda sensor and this is often a vac leak, exhaust leak, or fuel filter/pump issue/injector issue.

Basically either your Lambda is working correctly so something else is causing the problem or it is still giving wrong readings in which case it is telling the ECU to put the wrong amount of fuel in.

Just a thought - is your coolant level dropping at all? Antifreeze kills O2 sensors very quickly and when they die they give similar symptoms to what you are seeing. I've seen this a few times on cars when the head gasket goes.

The engine is running in "Close loop" at idle, only I can see "Open loop" when hard accelerating or at first sec when engine breaking.
There is no coolant leakage, the same stable level. The O2 sensor was replaced to new one Denso DOX-0113 without any results.

Please take a look at the spark plugs, cause I'm not so skilled to evaluate if the mixture is lean or proper. Photos show spark plugs from cylinder one and two.

Hi,

I would have said the plugs look normal, see the following chart

www.atvriders.com/articles/how-to-read-spark-plug-colors.html

The Open loop/closed loop sounds normal as well. Once the sensors are warm it should be in Closed Loop most of the time, except hard acceleration (the O2 sensor is unreliable at setting the fuel ratio) and when engine breaking, there is no or very little fuel injected.

I am still wondering if you have the correct sensor, a DOX-0113 is a universal sensor and whilst it lists a Jimny as compatible, the crimp connectors are known to cause problems.

If it isn't the O2 sensor, or a head gasket, then it might be a fuel issue or one of the other sensors, most likely the MAF.

If you disconnect the MAF, it will run on the inbuilt map in the ECU, if this runs better then suspect your MAF.

I found the waveform summary in the Jimny Service Manual, the O2 output waveform at idle definitely should be different whereas the heater circuit looks great (see attached file). I disconnected the MAF and the engine runs without big difference whereas the O2 goes very reach. Tomorrow I'll check the MAF by the scope but I re changed it with other (Denso DMA-0113) and the problem was the same, maybe the wiring issue?
How about the fuel system, maybe should I change the fuel filter? The car has about 230.000km and nobody change it before...