Check engine light has intermittently been coming on.

Code reads P 0138... 01/01.

Was wondering how to determine which sensor is bad?

I've read it's mostly likely the upstream as it takes most of the abuse...

Not sure why my scanner doesn't how there is (2) sensors and tell you 01/02 or 02/02...

This is the scanner I have....



Any recommendations on which replacement sensor to buy....bosch?

 

The P0138 code is for the rear O2 sensor on bank 1.

 

Do NOT buy Bosch. Dakota's hate them in general. Use NTK or Denso.

As dolittle says, P0138 is a 01/02 sensor, downstream, bank 1.

You don't need a scanner to read the codes. You might want to verify it if your reader is showing an 01/01 code, upstream.

To check codes: with the key OFF, turn it to RUN (not start), then OFF, back to RUN, then OFF, finally leave it in RUN. Codes will display in the odometer window.

 

Thanks guys.

I've only got 1 downstream sensor that I can see...so not sure if the bank 1 is relevant? Is the bank 1 vs. bank 2 only relevant on ca. emissions?

I tried that on/off/on/off/on method and came up with the P0138 code again.

This has been an intermittent issue, haven't been able to nail down any specific circumstance that trigger it.

It went for weeks without triggering the check engine light then just triggered again the past few days.

This has only been my truck for a few months, and my Dad who I bought it off said he had to through the check engine light a few times as well.

Haven't noticed any real performance issues.....

Wanted to get your input on if a faulty sensor is typically an intermittent type problem or I more likely have a wiring or some other electrical issue?

Thanks again for the help.

 

IIRC bank 1 is driver side, bank 2 is passenger side. 01 is upstream and 02 is downstream.

Wait…if you have the single cat instead of three then yes I think the codes are a little different...

 

If you have the NAA emissions package you'll only have 2 O2 sensors, 1 upstream and 1 downstream.


There are two other emissions packages, NAS and NAE (one is CA) they use 4 O2 sensors.

 

If a new sensor does not fix it, Chryslers recommendation is to replace the PCM. Mines (a ram, but same platform technically) got the same issue, sensors dont fix it.