The dreaded check engine light!

[dan filipi]

I'm getting a P0059 error on my van.

A customer plugged his dealy into it to give me the code, HO2S Heater Resistance Bank 2 Sensor 2.

I cleared it once by disconnecting the battery for 15 minutes then again with his code reader after the check engine light came on a couple days later.
It's running a bit slow at idle recently but otherwise running fine.

So I'm not throwing expensive parts at this to fix it, what tests can I do to confirm the bad part?

Don't know if this is related or not but it might help to know that this error code showed up a day or 2 after the battery was almost dead on Monday.
That same day I had a new higher capacity alternator installed. The old one was reading low voltage and fluctuating.

 

[steveb123]

Check the wiring connection, and for juice at the heater circuit at the sensor, before changing out the sensor.

 

[cooltech]

Dan the only time the o2 heater comes on is when it needs too warm it you can check the wiring
but the only way too fix is replace the sensor you will not get much of a voltage reading because
they are pcm controlled approx .5 too 5volts that will tell you that the pcm is working but not the
sensor.

 

[scdmarx]

In my experience an 02 "HEATER" code always requires replacement of the 02 sensor. It's powered by B+ & ground, controlled through the PCM. Theoretically, there could possibly be a problem with power and ground. You could check this with a volt meter. But I'd bet money you'll end up replacing the sensor. 02 sensors are wear items similar to spark plugs.

The 02 sensor don't respond until it reaches a certain temp to work. The heater part is to reach that temp sooner to get the car into closed loop as soon as possible. The heater is built into the sensor, so you'd replace the unit.

Bank2Sensor2 will be the one after the catalytic converter on the bank opposite #1 cylinder is on.

Sensor 2 purpose is to monitor catalyst efficiency, mainly. But it also influences the PCM's decision process in monitoring/adjusting fuel trims over time.

Simple to replace. Unplug the wires, use a 7/8" box end wrench to get it loose. If you need to, cut the plug off the old one to get the box end to fit over. The new one can be tightened with the open end. Use the anti-seize that comes with it and don't over tighten.

 

[joedrum]

:cheeky: tape over light .....

 

[dan filipi]

It went a couple days before the error popped up again.
Is this a common symptom?

 

[mcgovern61]

:cheeky: tape over light .....

That is a very technical response Joe! :smilie_happy:

 

[dan filipi]

:cheeky: tape over light .....

Nah, I totally agree with all the smog devices now, no more smog alert days in L.A for over 25 years are because of them.

 

[scdmarx]

It went a couple days before the error popped up again.
Is this a common symptom?

Yes. For the light. By disconnecting the battery, you reset all the monitors and memory. You may have to drive a couple miles for it to relearn idle and....?

It took driving time to run the 02 monitor after battery disconnect/reset..

 

[scdmarx]

:cheeky: tape over light .....

I prefer finger nail polish, myself. :good:

 

[dan filipi]

It went a couple days before the error popped up again.
Is this a common symptom?

Yes. For the light. By disconnecting the battery, you reset all the monitors and memory. You may have to drive a couple miles for it to relearn idle and....?

It took driving time to run the 02 monitor after battery disconnect/reset..

Thanks for the details Ron, I feel more confident replacing it will fix the problem.

 

[joedrum]

im glad its getting worked out ... :clapping:

 

[David Mantle]

:hi: Never had such a warning light on my wing. :lazy:

 

[scdmarx]

:hi: Never had such a warning light on my wing. :lazy:

That's good because there's no place to plug in a "thingy" to see the codes. So it all works out. :music3:

 

[AApple]

I'm wid Ron...gotta put a new-un on. The only other possible cause would be if the connector itself had a problem, and normally, if the heater circuit is shorted, it effects other components, too.

DTC P0059
CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the powertrain control module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater. When the heater is in the ON state, the PCM will pulse the heater OFF for a duration of 50 ms, once per second. The PCM calculates the heater resistance on a cold start. This diagnostic will only run once per ignition cycle. If the PCM detects that the heater calculated resistance is not within the expected range, the following DTCs will set:
- DTC P0053 for HO2S bank 1 sensor 1
- DTC P0054 for HO2S bank 1 sensor 2
- DTC P0059 for HO2S bank 2 sensor 1
- DTC P0060 for HO2S bank 2 sensor 2
CONDITIONS FOR SETTING THE DTC
The PCM detects that the affected HO2S heater calculated resistance is not within an expected range at engine start-up for 1 second.

B2S1 will be the front sensor on the passenger side... :good:

 

[dan filipi]

Would this thingamajigger affect the warm idle?
It seems to be idling a tad slower.

 

[joedrum]

huh ....hmmmmm i better get my pull ups on ....oh my :hihihi:

 

[cooltech]

It can but most ofthe time only affects fuel mileage if idle is slower could be caused by o2 sensor due too
pcm trying too get the timing adjusted and air fuel if it can not it will set codes and return too
basic settings too keep the engine running and too keep perfrmance as high as possible

 

[dan filipi]

What an awesome group we have here!
Before posting this morning I Googled the code and got all sorts of random answers, non specific.
Nothing like the info I got from you all in less than 2 hours after posting!

So......A couple more questions,

my favorite auto parts dude says there's 4 of these little bastards on my 06 Chevy Express 4.8 3/4 ton.

The exact code I'm getting is "H02 Bank 2 Sen1 Heater Resistance"
He says that code means side with cylinder number 2 and on the engine side of the Cat.
Is this correct?

 

[scdmarx]

Would this thingamajigger affect the warm idle?
It seems to be idling a tad slower.

I really don't think the 02 heater would do that. I'm afraid to rule it out because I've seen stranger things.
I am totally assuming that when you said the light came on again that it was the same code?
How much lower is it idling? Enough to stall at stops? Does it go below 500-550 rpm in gear with your foot on the brake?
If it still acts ok, but you just notice a little bit lower idle than it had before, it could just be that you reset something back to default when you disconnected the battery. (?)