Merry Christmas. I have a 2006 Lexus GS 300 AWD with 135,000 miles. Initially got three errors codes P0003 Fuel Volume Reg Control Circuit Low, P0158 BK2 S2 High Voltage and P2198 BK2 S1 Stuck Rich. I cleared the codes and P0158 Bk2 S2 High Voltage is the only error code.
Wondering if I might have fouled or bad fuel injector(s), a defective fuel pump or regulator, a vacuume leak or just need to replace 1 or more 02 sensors. Consistently use Premium Gas over 16 years.. The High voltage readings on B1 S1/S2 is confusing along with the error code P0158 triggering on Bank 2 S2 with normal voltage reading as well...
Bank 1 sensors are original and Bank 2 sensors were replaced at 85,000 miles, about 6 years ago.
Error Code P0158 02 Sensor Circuit High Voltage Bank 2, Sensor 2
Sensor Voltage Outputs on last reading
B1 S1 3.3 V
B1 S2 .66 V
B2 S1 3.3
B2 S2 .68V
CAT Temps 451 C
Fuel Trims all within normal range
Absolute Throttle Position B above normal range at 46.7%
Absolute Throttle Position in Range 14.5%
MAF Sensor inspected and clean
I have the data in a 2 page PDF file. Could not figure out how to post with the question.
See the post entitled Read this first near the top of the topic list. As you would for a photo or video you upload it to a file sharing site and post the link here.
It would be helpful to look at the Freeze Frame data from when that P0158 code is set
I have the data in a 2 page PDF file. Could not figure out how to post with the question.
You really just want to determine if bank 2 was actually running rich at the time that solitary P0158 code was set after clearing all the codes
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So in Freeze Frame: B1S1 & B2S1 A/F sensor voltages (for comparison)
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And the same for B1S2 & B2S2 O2 sensor voltages (for comparison)
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Also fuel trims on both banks (for comparison)
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Engine RPMs and the ECT temp
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It's a good starting point to see if you go down the path of intermittent high voltage on the B2S2 O2 sensor due to an intermittent circuit issue or intermittent high voltage on the B2S2 O2 sensor due to an intermittent too rich condition on bank 2 (it's intermittent because those voltage values you posted wouldn't set a code)
No CEL for several starts and a small trip. After the car sat for a few hours and restarted and got the Error Code P0158 For Bank 2 Sensor 2.
Very odd there is no voltage to B1S2
Freeze Frame with P0158
Error Code P0158 02 Sensor Circuit High Voltage Bank 2, Sensor 2
B1S1 & B2S1 A/F sensor voltages 2.459 V and 2.5 V
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B1S2 & B2S2 O2 sensor voltages 0 V and 1.275 V
Fuel Rail Pressure: 13580kPA
ST Fuel Trim B1 and B2 -20.3% and -20.3%
LT Fuel Trim B1and B2 -6.3% and -3.1%
CAT Temps B1 and B2 376/292C degrees 376/292 C degrees
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Engine RPMs and the ECT temp 1574 rpm and 13C degrees
What a difference from the Live Data. In your top post the A/F sensor scanner voltages were at 3.3v. Couldn't be more perfect. And you mentioned that your fuel trims looked good
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But in the P0158 Freeze Frame Data both A/F sensors are reading 2.5V. That's really rich on both cylinder banks and they're reading it with -25% fuel trims on both cylinder banks already
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Your problem is that this is intermittent and you have to catch it in the act to diagnose it. When it sets the code hook up your scanner, Live Data, and force a lean condition while watching the A/F voltages and O2 voltages (if your scanner can graph them do it that way). You can pull off a large vacuum line from the intake manifold like the one for the evap purge valve
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The A/F voltages should shoot up to around 4 volts and the O2 sensor voltages should shoot down to around 0 volts. That will prove they are responding right. You can do the opposite and force an even richer condition too by spraying starting fluid into the intake. The A/F voltages will go even lower than when the code was set and it could be helpful to see if you can force that B1S2 sensor up from 0 volts.
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If the sensors respond then it's time to start checking off the things that can cause an intermittent rich condition on both cylinder banks at once. There isn't much. It could be 2 leaky fuel injectors 1 on each cylinder bank. But probably not.
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Fuel Pressure Regulator (you originally had a code for that although the fuel pressure in your Freeze Frame wasn't excessive if the fuel pressure sensor is telling the truth). Then on the sensor side, MAF, IAT, and ECT sensors. On the component side, a sticking open purge valve, or the exhaust gas recirculation system, or even a sticky pcv valve. (You'd think that would create a lean condition but I noticed in the freeze frame the code was set when the ECT read 55F. The engine was cold but you had shut it off a few hours earlier. So pull the dipstick out and smell it to make sure this isn't a "fuel contaminated oil" issue
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That's all I got
Jack, the mechanic i work with did not find any issues with the Fuel Pressure Regulator or the other areas or the car you suggested I check. He concluded that 3 of the Sensors were bad and i had all 4 sensors replaced. He thinks the direct fuel injection design on this model of car leads to a lot of carbon buildup in the engine which they are known for and might be the cause of the sensors failing. Really appreciate your taking the time to provide your guidance as I wanted to be convinced another issue was not causing the bad A/F O2 sensor readings before I replaced. them.