Mode $06 Test report

[roks]

Hi,

Doesw anyone know what this means? I got this from the Torque Pro test mode. The O2 sensors appears to be working, although I dont understand O2 Sensor 2, is it supposed to be flat line in the middle, ie 0.45 volts? Mine flat lines at 0.2v to start with and then creeps up close to 0.8v and stays there at idle, if I hold at 2000rpm it goes back down to around 0.2v.

There are no fault codes, other than the P0420 that I've had for over a year, yet the car passes CO2 test with flying colours.

Test report:
------------------
TID:$01 CID:$01
- Rich to Lean sensor threshold voltage(constant)
Max: 38
Test result value: 42
FAIL
----
TID:$04 CID:$01
- High sensor Voltage for switch time calculation
Min: 3,276
Test result value: 10,268
PASS
----
TID:$04 CID:$02
- High sensor Voltage for switch time calculation
Min: 3,276
Test result value: 8,358
PASS
----

[Anthony Poli]

Hi,

From experience with a 2001 Corolla GS, and having O2 sensor issues. You should be able to look at both sensors while the car is idling whilst parked up, the first sensor signal change at a similar speed to a heart beat, and the second sensor should be fairly constant and vary slightly at much slower rate.

From my basic knowledge, the first sensor is before the cat and fluctuates as the engine management is regulating fuel amount with the amount air coming in. Lean to rich and back, the sensor after cat responds to the end results which should be stable.

The problem i had, the second sensor was sticking either high or low, but to make things worse it was intermittent and it was never picked up at a service.

The fuel economy went down as the problem became more perminant.

I hope this helps.

[roks]

Thanks for your response Anthony,

When parked, the post cat o2 is high at idle rpm or low a when rev is 2000rpm.

above is when at idle around 650rpm

this one is when I blip the throttle to 2000rpm.

I am yet to find out where this constant line should be in a toyota. I checked my brothers car,  a corsa 1.2, his post cat o2 is in the middle with tiny fluctuations around 0.45v.

Did you get yours fixed? Was it just the sensor? Are you able able to confirm if it constant in the middle?

[Anthony Poli]

Mine was actually giving the codes for the sensor, one was reporting it was not varying and the another was to do with the circuit.

It was typical each time the car went in for a service no mil light showing. After telling them at the local dealer, they replaced it.

After that the sensor was reading mid way like you said the corsa was and the fuel economy came back to normal.

It started around the time when some of the petrol from supermarkets was that imported fuel which caused lots of problems.

 

[roks]

I guess yours were sensor specific so easier to fix. 

I am wondering if toyota just programmed the ecu to throw this code after certain number of years they think the cat will last?

[Anthony Poli]

I can't remember how much my local toyota charged, most of the cost was for the labour. Since it was right under the car, i didn't fancy having a go myself. Did think about Parking with 2 wheels on the pavement and getting under, but wasn't confident to have a go myself.

In our case it was contaminated fuel as the other corolla was 1 year older and didn't have the same issue. Just had fuel from a different place.

 

[Devon Aygo]

Taken from Toyotas diagnostic info for P0420

[roks]

Thanks Devon,

I think I'll have to get a smoke test to see if there is a exhaust leak ahead of the cat, maybe the down pipe gasket.

[roks]

So I took the car for the MOT, they tested the exhaust, not leaks and the car past the MOT with flying colours, no issues.

Before the MOT I had reset the MIL and drive around for a while until the monitors were in a ready state. After the MOT test I checked with Torque Pro, the above test came back as passed.

I then hooked it up to Techstream, that too came back as passed for CAT test, so what the heck is causing the P0420 to keep returning. I'll see how long it takes before it reappears this time.

 

[Anthony Poli]

So I took the car for the MOT, they tested the exhaust, not leaks and the car past the MOT with flying colours, no issues.

Before the MOT I had reset the MIL and drive around for a while until the monitors were in a ready state. After the MOT test I checked with Torque Pro, the above test came back as passed.

I then hooked it up to Techstream, that too came back as passed for CAT test, so what the heck is causing the P0420 to keep returning. I'll see how long it takes before it reappears this time.

 

That could be the sensor. When mine was starting to go, it did it once and the next time was 12 months later. Then it became more frequent, but my codes were 137,138,139. In the end during a Saturday morning shopping trip, it came on during the first start and by the time I got home the mil light had reset itself. The mpg had dropped to about 24-27, from the usual 40.

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[ThisGuy]

My car says tid$04 cid:$60 high sensor voltage for switch time calculation. I have an 01 corolla.