C230 Sport Coup

Can anyone here give me a definitive answer as to what I need to do to get rid of the P0171. ? Attached some info, let me know what else is needed!

So, I have a P0171 error and it's keeping me from passing smog.
Smog tech suggested my leaky brake booster (it hisses and is sucking in some air) might be the problem. But it's been like that for a long time.

MAF hasn't been replaced for a long time though I clean it religiously. Not replaced since I took over maintaining it when the 100K extended warranty expired years ago, (now at 213K !).

I replaced the Cat about a month ago, it was shot. Was getting P0171 even before I replaced the Cat.

Downstream O2 sensor is original but is still putting out a signal. (I think? Passes readiness test)
Upstream O2 sensor was replaced at 100K miles.
Never touched EGR valve.

When I use "Torque" phone app to read diagnoses I get a failure in Mode 6
Test report: Mode $06 report generated by Torque for Android
TID:$01 CID:$01
- Rich to Lean sensor threshold voltage(constant)
Max: 64
Test result value: 115
FAIL


Also checked O2 sensors- Attached are graphs at idle.

BUT the readiness checks show O2 sensors as ready.

Downstream sensor doesn't seem to get much movement.

It followed the upstream sensor almost to a T before I replaced the Cat, which is one of the indicators of a bad cat.


Here's the upstream O2 sensor at idle....
crap the downstream screenshot got lost due to my crappy phone, will re-do. But basically it's a straight line show just under .5V



In any case, can anyone here give me a definitive answer as to what I need to do to get rid of the P0171.


------------------
TID:$01 CID:$01
- Rich to Lean sensor threshold voltage(constant)
Max: 64
Test result value: 115
FAIL
----
TID:$02 CID:$01
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 19
PASS
----
TID:$02 CID:$02
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 12
PASS
----
TID:$03 CID:$01
- Low sensor Voltage for switch time calculation
Min: 45,875
Test result value: 46,053
PASS
----
TID:$01 CID:$01
- Rich to Lean sensor threshold voltage(constant)
Max: 64
Test result value: 115
FAIL
----
TID:$02 CID:$01
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 19
PASS
----
TID:$02 CID:$02
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 12
PASS
----
TID:$03 CID:$01
- Low sensor Voltage for switch time calculation
Min: 45,875
Test result value: 46,053
PASS
----
TID:$05 CID:$02
- Rich to Lean sensor switch time(calculated)
Max: 21,568
Test result value: 21,557
PASS
----
TID:$05 CID:$03
- Rich to Lean sensor switch time(calculated)
Max: 30,368
Test result value: 21,557
PASS
----
TID:$06 CID:$01
- Lean to Rich sensor switch time(calculated)
Max: 25,000
Test result value: 283
PASS
----
TID:$06 CID:$02
- Lean to Rich sensor switch time(calculated)
Max: 25,000
Test result value: 203
PASS
----
TID:$08 CID:$01
- Maximum sensor Voltage for test cycle(calculated)
Min: 154
Test result value: 255
PASS
----
TID:$09 CID:$01
- Time between sensor transitions(calculated)
Max: 1,200
Test result value: 260
PASS
----
TID:$0a CID:$01
- Sensor period(calculated)
Max: 32,943 Min: 32,593
Test result value: 32,919
PASS
----
TID:$0a CID:$02
- Sensor period(calculated)
Max: 49,151 Min: 16,384
Test result value: 47,639
PASS
----
TID:$01 CID:$01
- Rich to Lean sensor threshold voltage(constant)
Max: 64
Test result value: 115
FAIL
----
TID:$02 CID:$01
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 19
PASS
----
TID:$02 CID:$02
- Lean to Rich sensor threshold voltage(constant)
Max: 64
Test result value: 12
PASS
----
TID:$03 CID:$01
- Low sensor Voltage for switch time calculation
Min: 45,875
Test result value: 46,053
PASS
----
TID:$05 CID:$02
- Rich to Lean sensor switch time(calculated)
Max: 21,568
Test result value: 21,557
PASS
----
TID:$05 CID:$03
- Rich to Lean sensor switch time(calculated)
Max: 30,368
Test result value: 21,557
PASS
----
TID:$06 CID:$01
- Lean to Rich sensor switch time(calculated)
Max: 25,000
Test result value: 283
PASS
----
TID:$06 CID:$02
- Lean to Rich sensor switch time(calculated)
Max: 25,000
Test result value: 203
PASS
----

End of report.

C230 Sport Coup

Found this doc on O2 sensors, thought I'd attach it.
I seem to recall torque saying my car was not running in closed loop.
There seems to be many ways to check the upstream sensor, such as pullinh a vacuum line, or spraying propane into the intake, but how do you test the downstream sensor?

Maybe if I put my stock pulley back on I might pass? That should help to reduce leanness?

kirax2

just craiglist some illegal smog shop area in Norcal and get it pass smog

tommy

They have these things called "shops" where they truly know what they're doing, and have the experience to correctly diagnose your issue. I hear they can be helpful!

C230 Sport Coup

Shops? That's what Roxy like to do. Shop.
I don't need no stinkin' shop!
For the price of just the diagnostic, and I could buy both 02 sensors.

tommy

And hope that solves the problem, of course.

C230 Sport Coup

Well, thing is, I have one O2 sensor that's original (downstream) and one that has over 100K miles (upstream) so per mercedes they should be replaced either way.
Thing is I'm not really clear on what the purpose of the downstream sensor is, or if it would play a part in getting the lean condition.
Good news is my evap system finally went ready. So if I can fix the lean condition, (perhaps put the stock crank pulley back on?) I can pass smog.

tommy

Just pay someone off and get passed already. Sheesh!

C230 Sport Coup

Political corruption has it perks.
Ah, to be NJ again and be able to just pay people off.
Cali, people are so by the f'ing book.