Just bought an 07 GX470! but I have a persistent P0430 code (2 Viewers)

[intoodeep1113]

I just bought this GX 470 with 102K on the clock. It is in really great condition for the most part. I searched for quite a while and this was the best condition I found in my area.
When I got it home, it came up with with a CEL and a P171, P174, and P430 code and some significant drive-ability issues. I took it to lexus, they said replace the bank 2 sensor 2 O2 sensor, and if that doesnt fix it then the cat is bad. They want $600 for the O2 sensor, but I opted to do it myself for $34 for the Denso O2 sensor. That cleared the P171, and P174 and the bogging down/loss of power when accelerating issue. Now I still have the P430.

Anyone here replace a cat? Looking at havinga universal Walker cat welded in. $90 parts, $150 labor. Anything I should check/do prior to this?


Also, I'm sure I'm obligated to post a pic if i expect any assistance! It is a bit dirty though!

Old vs New ride!

 

[danthemanx07]

Get a scangauge and just clear the 430 code. I have been doing this for a few years now. I have read that the sensors are very particular and that putting in an aftermarket cat might not get your code cleared.

 

[intoodeep1113]

Yeah, that's about where I am at now. Using torque to clear the code every day.

 

[HomersCanyonero]

First of all, the denso o2 sensors are oem. So, you are good there. What’s the part number on these denso o2 sensors?

P0430 and P0174 are codes on bank 2.

P0171 is on bank 1.

I would have replaced both upstream O2 sensors. And that’s what I did on mine to solve these codes. Replace the cheap stuff before going bankrupt on the cats.

 

[GXer04]

Check for exhaust leaks near the downstream o2 sensor. This fixed it for me when I had the same issue several years ago. Basically, it lets air leak in on the sensor and throws the code. Good luck.

 

[intoodeep1113]

Denso 234-4209 Oxygen Sensor was the one I bought. Required making up the harness though.

I also did this report. Maybe some here can interpret better than I!


Mode $06 report generated by Torque for Android
================================================

Vehicle Manufacturer: Lexus
Vehicle Calibration ID: 36084000

Test report:
------------------
MID:$01 TID:$8e
- O2 Bank 1 Sensor 1
Max: 19.898V Min: 0.199V
Test result value: 0.926V
PASS
----
MID:$01 TID:$91
- O2 Bank 1 Sensor 1
Test incomplete or dependant test failed
--
MID:$02 TID:$07
Minimum sensor Voltage for test cycle(calculated) - O2 Bank 1 Sensor 2
Max: 0.214V Min: 0V
Test result value: 0.136V
PASS
----
MID:$02 TID:$08
Maximum sensor Voltage for test cycle(calculated) - O2 Bank 1 Sensor 2
Max: 1.19V Min: 0.585V
Test result value: 0.664V
PASS
----
MID:$02 TID:$8f
- O2 Bank 1 Sensor 2
Max: 2.99784 Min: 0
Test result value: 0.59749
PASS
----
MID:$05 TID:$8e
- O2 Bank 2 Sensor 1
Max: 19.898V Min: 0.199V
Test result value: 0.987V
PASS
----
MID:$05 TID:$91
- O2 Bank 2 Sensor 1
Test incomplete or dependant test failed
--
MID:$06 TID:$07
Minimum sensor Voltage for test cycle(calculated) - O2 Bank 2 Sensor 2
Max: 0.214V Min: 0V
Test result value: 0.117V
PASS
----
MID:$06 TID:$08
Maximum sensor Voltage for test cycle(calculated) - O2 Bank 2 Sensor 2
Max: 1.19V Min: 0.585V
Test result value: 0.82V
PASS
----
MID:$06 TID:$8f
- O2 Bank 2 Sensor 2
Max: 2.99784 Min: 0
Test result value: 0.04758
PASS
----
MID:$21 TID:$a9
- Catalyst Monitor Bank 1
Max: 9.99393 Min: 0.29951
Test result value: 0.30286
PASS
----
MID:$22 TID:$a9
- Catalyst Monitor Bank 2
Max: 9.99393 Min: 0.06222
Test result value: 0.05825
FAIL
----
MID:$3d TID:$c9
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 0.176kPa
PASS
----
MID:$3d TID:$ca
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 2.266kPa
PASS
----
MID:$3d TID:$cb
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 1.32kPa
PASS
----
MID:$3d TID:$cd
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 1.32kPa
PASS
----
MID:$3d TID:$ce
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 2.002kPa
PASS
----
MID:$3d TID:$cf
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 1.452kPa
PASS
----
MID:$3d TID:$d0
- EVAP Monitor (0.020")
Max: 32.767kPa Min: 0kPa
Test result value: 2.442kPa
PASS
----
MID:$42 TID:$91
- O2 Heater Monitor Bank 1 - Sensor 2
Max: 33,179mOhm Min: 0mOhm
Test result value: 22,329mOhm
PASS
----
MID:$46 TID:$91
- O2 Heater Monitor Bank 2 - Sensor 2
Max: 33,178mOhm Min: 0mOhm
Test result value: 26,861mOhm
PASS
----
MID:$71 TID:$e1
- Secondary Air Monitor 1
Max: 655.34998g/s Min: 2.01g/s
Test result value: 4.8g/s
PASS
----
MID:$71 TID:$e2
- Secondary Air Monitor 1
Max: 4.99kPa Min: 0kPa
Test result value: 0.13kPa
PASS
----
MID:$71 TID:$e3
- Secondary Air Monitor 1
Max: 655.34998kPa Min: 0.99kPa
Test result value: 7.77kPa
PASS
----
MID:$71 TID:$e4
- Secondary Air Monitor 1
Max: 19.99kPa Min: 0kPa
Test result value: 0.54kPa
PASS
----
MID:$71 TID:$e5
- Secondary Air Monitor 1
Max: 655.34998kPa Min: 15.89kPa
Test result value: 87.16kPa
PASS
----
MID:$71 TID:$e6
- Secondary Air Monitor 1
Max: 19.99kPa Min: 0kPa
Test result value: 0.58kPa
PASS
----
MID:$71 TID:$e7
- Secondary Air Monitor 1
Max: 655.34998kPa Min: 1.4kPa
Test result value: 1.75kPa
PASS
----
MID:$a1 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Monitor General Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a1 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Monitor General Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a6 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a6 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a7 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a7 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a8 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 7 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a8 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 7 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a9 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 8 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a9 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 8 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----


End of report.

 

[intoodeep1113]

Well I ran some CRC "Guaranteed To Pass" and I had no change. every time I drove I would get the CEL for P430 or at least the pending trouble code for P430. I took the truck to Midas and they said they wouldnt be able to tell if it was the front of back CAT causing the issue. (They said the back cat can be clogged enough to let excess gases build up and affect the O2 sensor before it.) $1250 to replace both cats on that side. They recomended replacing the upstream O2/ Air-Fuel Ratio sensor prior to the work. Not wanting to get into all that right now, I purchased an O2 sensor spacer and Installed it 2 days ago. so far no CEL or pending code and an improvement of 1-3 MPG! 50 miles is too soon to really tell the whole story, but it looks good so far. The spacer was $8.

 

[skeptastic]

Well I ran some CRC "Guaranteed To Pass" and I had no change. every time I drove I would get the CEL for P430 or at least the pending trouble code for P430. I took the truck to Midas and they said they wouldnt be able to tell if it was the front of back CAT causing the issue. (They said the back cat can be clogged enough to let excess gases build up and affect the O2 sensor before it.) $1250 to replace both cats on that side. They recomended replacing the upstream O2/ Air-Fuel Ratio sensor prior to the work. Not wanting to get into all that right now, I purchased an O2 sensor spacer and Installed it 2 days ago. so far no CEL or pending code and an improvement of 1-3 MPG! 50 miles is too soon to really tell the whole story, but it looks good so far. The spacer was $8.

Many years later, but in case you're still around... what ever happened with this situation long-term? Also looking into a used GX 470 and it seems like the P0420/P0430 codes are harder to solve than the other known issues with the vehicle (exhaust manifold, etc). Thanks for any insight!