Time to replace O2 sensor?

lunytnz · February 4, 2018

Every once in a while (4-5 times over the past 9 years), I've gotten a P0161 (O2 heater performance Bank 2, downstream, after cat) code, but there's never been anything noticeable as far as runability.

I got the P0161 in December and again this week. But, now I'm seeing 2 new codes I haven't ever seen before: P0155 (O2 sensor heater performance Bank 2, upstream) and P1153 (O2 sensor insufficient switching Bank 2, upstream).

I figure the P0161's may have just been anomalies in the past, but now that I'm seeing BOTH the P0155 and the P1153 for the upstream sensor that it might be a sign the sensor is malfunctioning. Or, should I just wait and see if it's just another anomaly?

If you've gotten P0155 and P1153 codes, did replacing the sensor fix the problem?

Description

swathdiver · February 4, 2018

Also check the wiring harness, the heater wires specifically. Could also be the ECM.

Colossus · February 5, 2018

year, make, model, engine, miles?

lunytnz · February 5, 2018

1 hour ago, Colossus said:

year, make, model, engine, miles?

Sorry about that (normally I make sure that's covered)

99 Yukon 5.7L 190,000 miles

Colossus · February 6, 2018

Yes sir, your O2 sensors have retired after many faithful years of service, replace em all. Inspect the wiring up to the wiring harness and connectors well. Get good brand O2 sensors, Bosch or Delco are my choices. Your cat converter may be done for as well.

lunytnz · March 3, 2018

Thanks! I've been looking at either Bosch or Delco. Will I really need the special O2 sensor socket? (it looks like it's 7/8")
Is the upstream sensor accessible from the engine bay? Or will I need to get at it from under the rig?

GhostWriter · March 4, 2018

On ‎3‎/‎3‎/‎2018 at 1:36 AM, lunytnz said:

Will I really need the special O2 sensor socket?

On something that old, I'd probably clip the wires and use a standard deep well (flank drive) socket. The special sockets aren't usually that strong.

swathdiver · March 4, 2018

Yeah, 7/8 or 22mm. I can only get them from the bottom.

lunytnz · September 1, 2018

Thanks for the tips! It took me a while to get to it, but I replaced the upstream sensor. The most difficult part was dealing with the plastic pin that holds the connector in place; I tried to get the plastic pin (on the back of the wiring connector) free from the holder, but it broke free from the connector first. Ultimately, I couldn't do it (don't have enough access to get in there with a pair of needle-nose pliers to pry it out), so I just left the old pin in place and stuffed the connector back up near it. It seems fairly secure, like it's not likely to go anywhere. The little blue 'security' pin was a bit of extra fun, but I got lucky with a screwdriver and was able to pry that out so that I could disconnect the connector.

Once I got all my tools together, it only took about 20 mins. I tried to loosen the downstream sensor, but I wasn't as lucky as with the upstream, so it will have to wait for another time. It looks like the connector will be extra fun because it's on top of the transfer case and it seems I'll have to disconnect it by feel.