ECU throws P0134 (O2 sensor response) but everything is ok

[coolchip]

Hey,
I drive an jdm itr dc5 with a PRC ECU. I've got a Gruppe M air intake and a Fujitsubo RM-01A. All the other parts are stock.
My KManager version is 1.5.1.0.

Sometimes, when I drive or when in idle, I get the P0134, that says "no respose from O2". I look at the AF and it shows 15,37. After restarting the motor, everthing is ok. The lambda shows regular values.
Sometimes I can drive an hour and no error accours.
If I disable the P0134, the lambda shows regular values all the time. No freeze at 15,37.

If you look at the datalogs, you can see, that first comes the MIL, showing P0134, and AFTER that the AF goes to 15,37 and freeze. Before the MIL comes, everything seems ok and the lambda shows regular values.

Before the KPro I drove a Mugen HOA ECU which shows no error. And even a stock PRC DC5 ECU from a friend shows no error.
Can you please help me?

[taitcw]

It sounds like the same problem I had. The A/F ratio is stuck right?

Once ECU threw P0134, it stops driving the O2 sensor. You should be able to revive its operation by [Online] > [Clear DTCs].

After a very short while, your A/F ratio should be back to normal. For me, A/F would stuck again if engine idles for too long.

I fixed the problem by replacing the sensor, but it wonder if it is the real cause??

@Hondata: Do you know how the ECU drives the O2 sensor? I probed the two heater pins, I think the ECU PWM drives the heater at engine startup then slowly back it down to zero. Sensor needs to be warmed up to working temperature ASAP to work in order to reduce emission I guess? But I dont know why the sensor would stop responding and ECU throws P0134...

[coolchip]

Yes, when the P0134 comes, the afr gets stuck. But only AFTER the P0134. Bevor the error the afr is working fine (please look at the datalogs). So why throws the ECU this error?

Yes, if I clear the DTCs, the afr works normal like before. And it seems, that this error only occurs at idle.

I don't belief, that the o2 sensor is broken. If I put the stock ECU in my car, it throws no error.

My question is, why throws the ecu this error while the sensor is still working fine.

[taitcw]

You are right, why stock ECU works fine with the same O2 sensor...

Have you tried to Erase ECU and upload a brand new kal, then upload your own kal?

What KM version are you running?

[coolchip]

Yes, I tried to erase the ECU several times. I also tried to load several kals into the ecu. All with the same P0134 problem.

I hazard a guess. Some K20 ECUs have wideband, some have narrowband. A narrowband o2 sensor in closed-loop is alternating between "too rich" and "too lean" all the time. If the narrowband sensor shows rich or lean for a specific time, something is wrong and the ECU throws P0134. That's the correct behavior in this case.
Cause the wideband o2 sensor is able to show afr between "too rich" and "too lean" it is possible, that the afr oscillate a little bit over or under the 14,7:1 mark for a while (closed-loop). Imho that's normal for wideband but not for narrowband. If the KPro isn't able to handle that different error detection between narrowband and wideband it throws a P0134. But that's anyone's guess.

I would be glad if someone from hondata can comment this.

[Hondata]

P0134 means that the o2 sensor heater internal resistance is high. Normally the internal resistance falls as the o2 sensor warms up, but if the resistance remains high either the heater element is broken or there is additional resistance in the wiring. The use of the KPro changes none of the wideband control logic in the ECU.

[coolchip]

Thanks for your answer. This could be the explanation why this error often comes in idle.

But now I'm a little bit confused. If P0134 means, that die heater resistance is too high after warm up, what means P1167?

[Hondata]

P1167 is also determined by measuring the o2 sensor heater internal resistance, but the P1167 test only runs for the first minute after start up.

[Spunkster]

post your calibration

[coolchip]

Ok, sounds good. But why does the stock ECU don't throw the error?

@Spunkster
I'm at the beginnig of the kalibration process. I took the DC5 kal from hondata (K20a-itr.kal), retarded the ignition in some regions and changed some parameters. I know it runs too rich.

[yellowle]

I have the very same problem now - used the same PRC ecu and o2 sensor for a year without any previous problems at all. This has only started to happen with the latest software rel 1.5.1.0 over the last few weeks.

Once the error occurs - I pull over and turn the engine off and start again - the system seems fine. Yesterday this happened - I can drive for 5 mins and the error occurs - I restart the engine - and can drive 60mins without a problem - it seems totally random. I have just re-soldered all the connections (before I read this thread) to eliminate any dry joints - but they all looked good to me.

[coolchip]

@hondata
so, you are sure, that my o2 sensor is broken?

@yellowle
with which version you worked before?

[yellowle]

hi coolchip

i have been using a number of "beta" versions of K-PRO and they all seemed OK until i downloaded this last version - so the version prior may of been 4 weeks old. Not too sure of the version number!

but it sounds like we have exactly the same problem and I also have a JDM DC5 PRC ECU - surely it cant be coincidence

I will take it for another run on Saturday to see if it still does it.
Will keep you posted.

[yellowle]

OK I did two 1 hour runs this morning without a problem.

I have made 2 modifications since the problem arose
a) soldered the 4 connections where i spliced the 4 ecu and O2 wideband cables (these were previously crimped)
2) replaced the usb cable as i noticed that when I wriggled the connecter at the notebook pc usb that I lost connection. This was a cable issue as a good quality usb cable is firm/solid in place and did not break the connection.

I hope this helps and i will do more runs tomorrow to confirm all is well.

[coolchip]

I try to test it with an older KManager this weekend. Perhaps it works.

@yellowle
Why did you first spliced the O2 wires?