Source
r/MechanicAdvice•
andre2142

04 Toyota MR2 141k, Illusive P0136 code help

Ive been having trouble getting rid of this code for a while now. This is a 2004 Toyota MR2 Spyder, 1zz engine with 141K. I know tis pertains to the Bank 1 Sensor 2 (after cat.) and I've tried:

  • Had this issue before, Bought an OEM Denso sensor, P0136 after 3 months.

  • swapped "bad" Denso sensor to Bank1sensor1's place, P0136 only.

  • Got an aftermarket O2 sensor for bank1sensor2, P0136 only.

  • Used a Fluke 199c Scopemeter (negative connected to negative batt. terminal) measured the resistance for each o2 plug (3 total), and all have same resistance across all terminals.

  • I have a basic ODB2 live reader and the Bank1Sensor2 shows an maintains a 0.02v to 0.05v reading while the other sensors show an average of 0.760v at normal engine temp.

Just got the car back from a mechanic and he said his PC shows good readings, reset the code, paid 50 bucks (er..), code came back after driving it for 15 miles (err!..). He said if it comes back he will replace the O2 sensor with an OEM. I feel like I will be wasting my money if I do, what else can I do?

Posted Feb 15, 2020, 12:00 AM UTC

111
Mikaila31•

is there a wire broken further up then where the O2 sensor connects? I would try to find how to test continuity to and from the plug for the O2 sensor.

O2 sensors usually show a cyclic voltage like ^^^^^. I'd recommend trying torque app, it has a specific test for O2 sensors.

​

It may also be finicky about O2 sensors and getting a new OEM sensor would be a good way to rule that out.

​

We have an 05 MR2 FWIW changing the O2 sensor is pretty easy...

1
andre2142OP•

As far as I know, there's only one connector behind a tail light for that specific sensor, but I will trace for another connector. Hmm Ill try the Torque app to be sure. Right, Like I mentioned, the Denso Sensor lasted 3 months before showing that code.

The thing that bothers about that, is that the now "bad" Denso sensor is now on Bank1Sensor1's place and its not giving any issues on that bank.

But yeah, those sensors are pretty cake, I took it to the shop because this seemed like an electrical gremlin.

1
mister641•

Toyota’s hate aftermarket O2/Air Fuel sensors.

1
andre2142OP•

Yeah, you know...screw it, Im going to give a new denso sensor a chance.

1
mister641•

Give me a few minutes until I get to work and I’ll look at the diag tree and see what it says. There might be something else in there.

1
andre2142OP•

Sure thing, I'd appreciate it.

1
mister641•

Resistance across HT and B+ should be 5-10 ohms(pins 1-2) at 68 degrees. Most of the tree says replace the 02 sensor if the wiring is good. Spring for the factory one.

1
andre2142OP•

Thanks for the tip,

According to some of the sources I found, the sensor pin out below belongs to a 02 corolla, which I used since it I believe it also uses the 1zz.

=''=

2 | 1 =

4 | 3 =

=''=

I tested the resistance between 1 and 2 from all sensors and got the following (@ 70 degrees):

B1S2 (new): 16 ohm

B1S1(newish): 16 ohm

B2S1(old): 13.9 ohm

I then saw somewhere to test for proper power and connected a probe to the neg battery terminal and positive pos to socket 2 (HT+) on the engine side and got around 12v for all sensor sockets.

Then I tried testing proper ground by connecting a probe to the pos battery terminal and negative to socket 1 (HT-) on the engine side and barely got anything (~.01v) for all sensor sockets. I thought I was doing something wrong so I went for socket 3 and got 12v for all so im a little confused by that and the fact that Im over the range (5-10 ohms)

Lastly I ordered a new o2 denso sensor and cleaned the mass air flow sensor...eh just because.

1
mister641•

I wish I could have seen it earlier, but there was a tundra that exploded, so I was busy. Nothing else in the diag tree really jumped out as another option.

1
andre2142OP•

Dang thats intense, hmm my fluke is also an oscilloscope so I guess I can start probing the signals and look for differences at this point.

2
mister641•

It didn’t really explode, it spit a rocker and broke a timing chain. Still looking for broken parts. 😳

1