Common to have all 4 O2 sensors go bad?

[stiebertw]

03’ LX470 w/240k, owned for 6 months.

I’m up for inspection this month and need to take care of the error codes from my scanner.

Codes are: P0134, 0153, 0154 and 0430

Seems like all relate to the O2 sensors. I’ve read that people have replaced 1 or 2, but is it common that all 4, or in this case 3 possibly go out? The P0430 relates to the passenger side CAT, and an often fix is the downstream O2 sensor; but it could be the CAT itself.

If I’m going to replace 3 I might as well replace all 4. Has anyone else had the same issues and is it common.

Also, lights came on about 1 month of ownership.

 

[Eicca]

If you put a scan tool on it, what is the voltage reading from all O2 sensors?

In my old Lexus 1UZ, I had a situation where all four sensors would simultaneously flatline to 0v when giving the car some throttle. Turned out to be a bad EFI fuse. Couldn’t tell you the details, but replacing the fuse totally cured it.

(No it wasn’t corrosion on the fuse terminals or a simple ECU reset because I’d done those things dozens of times to try and fix it)

Check grounds and try a new fuse.

 

[2001LC]

Not common.

Something is going on upstream. Voltage issue perhaps, very poorly tuned engine, leak in exhaust, coolant leak into cylinders are just some of what may be going on up stream. It's also possible you've blockage in exhaust pipe muffler. Rodents or flood perhaps. Fuel pump or flow issues. combination of issues, are common at 240K miles.

A 240k mile ~20 year old, needs lost of TLC. Have you baseline it! Starting at battery and terminals, working thought engine. Not to mention all fluids.

 

[Coin]

I have one or two of those codes as well. I bought both downstream o2 sensors, but haven't installed them yet. The more I read, the less likely it seemed it was the sensors. I just periodically clear the code. Sometimes it's gone for months, sometimes a day. It seems temperature/humidity dependent I suppose I should get around to installing them and see what happens.

 

[2001LC]

I have one or two of those codes as well. I bought both downstream o2 sensors, but haven't installed them yet. The more I read, the less likely it seemed it was the sensors. I just periodically clear the code. Sometimes it's gone for months, sometimes a day. It seems temperature/humidity dependent I suppose I should get around to installing them and see what happens.

Which codes?

Remember prolonged idling is recommended against, in Toyota OM. That and or many short drives not getting to full operating temp and HWY speeds (higher RPM). Will set off CAT DTC. More so in the VVT engine (06-07)

1 O2 DTC set off, tend to be bad O2. More than one kicking off a DTC, is indication something up stream not as it should be.

 

[Coin]

Which codes?

Remember prolonged idling is recommended against, in Toyota OM. That and or many short drives not getting to full operating temp and HWY speeds (higher RPM). Will set off CAT DTC. More so in the VVT engine (06-07)

1 O2 DTC set off, tend to be bad O2. More than one kicking off a DTC, is indication something up stream not as it should be.

I'll check later today.

 

[Coin]

Which codes?

Remember prolonged idling is recommended against, in Toyota OM. That and or many short drives not getting to full operating temp and HWY speeds (higher RPM). Will set off CAT DTC. More so in the VVT engine (06-07)

1 O2 DTC set off, tend to be bad O2. More than one kicking off a DTC, is indication something up stream not as it should be.

I'm getting P0420 and P0430 Catalyst System Efficiency Below Threshold (Bank 1 and Bank 2)

 

[2001LC]

I'm getting P0420 and P0430 Catalyst System Efficiency Below Threshold (Bank 1 and Bank 2)

What year do you have?

 

[Coin]

2003 lx

 

[2001LC]

2003 lx

Unusual for 03 to get both at same time. What's going on with it, some history?
What have you done to correct?
Miles?
Last time tuned?
Coolant level in radiator and in reservoir, after 8 hour cool down?
Ran out of gas?
Heavy fuel smell?
Smoke?
Tick?

Do you or have you:?
Idle for prolong periods
Many short trips barely making operating temp, rarely if ever getting to HWY speeds.
Been in a flood.
Taken direct impact to both CATs
Have rodents issue and possible nesting in exhaust.

 

[Coin]

Unusual for 03 to get both at same time. What's going on with it, some history?
What have you done to correct? Nothing so far
Miles? 290K
Last time tuned? less than 60K miles ago
Coolant level in radiator and in reservoir, after 8 hour cool down? It was about a quart low
Ran out of gas? Nope
Heavy fuel smell? No
Smoke? No
Tick? No

Do you or have you:?
Idle for prolong periods No
Many short trips barely making operating temp, rarely if ever getting to HWY speeds. Lots of both
Been in a flood. Not to my knowledge
Taken direct impact to both CATs Not to my knowledge
Have rodents issue and possible nesting in exhaust. No

Beyond the above, it is a well maintained truck that runs very well. It was a grocery getter for most of it's life. The PO bought it from his sister and did some pretty extensive rehabbing (new radiator, ac compressor, headlights, all fluids changed, etc,) It feels like a dog compared to my wife's GX470.

 

[2001LC]

Beyond the above, it is a well maintained truck that runs very well. It was a grocery getter for most of it's life. The PO bought it from his sister and did some pretty extensive rehabbing (new radiator, ac compressor, headlights, all fluids changed, etc,) It feels like a dog compared to my wife's GX470.

The boxes you checked, need looking into

1. 1 qt low is concerning, when I couple that with radiator replacement. A red flag goes up. Overheated! I was likely just not properly top, but still needs consideration in the case of both CAT DTC.
2. Your short trips and prolong idling. Are both very hard on CAT and can damage them. The OM specifically warns "do not prolong idle". This is mostly likely in your case, cause of CAT issue. You may be able to correct without replacing CATS.

Here's what I do as first steps:
Look for signs of over heating. Swollen and or brown hard hoses.
Inspect head gasket, very closely for signs of coolant leak (red crust trails).

If above okay, then move on:
Clear codes.
Stop prolong idling.
Inspect for exhaust leak. From rear O2 forward is mainly what we're concerned with here today.
Keep short drives to a minimum. Take HWY drives to overcome bad effects of short drives. As CATs need around 2,500 RPM prolonged driving, to work at peak.
Top coolant properly. Watch close to see if level drops again. Make sure no clog in reservoir hose and it's cap, and that hose drops straight to bottom of reservoir.
Tune with new spark plugs, also Denso coil boot kit if they weren't replaced at last tune.
Make sure no vacuum leaks. Which last "tune", should have taken care of.
Make sure good oil & filter. I like Mobile 1 5W-30 regular or EP. Never use HM oil (high mileage oil)
Make sure good air filter, replace every 20K miles or sooner. Also that it is seated properly, as the seal gets curled on install very often.
Add 2 cans of 44K to a full tank of gas.
Do "Italian burns" (Drive at high RPM to supper heat CAT) Do this for 2 minutes at 4,000 RPM first time. Then drive normal for 7 to 10 minutes to cool CATs. If all went well (engine an feel okay) then drive at 4,800 RPM for 7 minutes, then normal. Then again for 10 minutes, then normal.) To cook gunk off CATs. It's like turning your oven to clean cycle.

You can also try CAT cleaners like Cataclean or Sledge hammer to name a couple. Read direction closely!

If coolant level keeps dropping, with no leaks. Then a combustion gas test in coolant would be good idea. Also compression test. Also note condition of each spark plug and from which cylinder they came from. Coolant is a CAT killer. It has the effect of basically steam clean cylinders. Which spark plugs can give clues of.

Head gasket leaks examples:
With under-shielding #1 & #2 off and a flash light, we can see almost every inch of head gasket.

Be using a flash light, we can see under intake manifold (98-05) with just engine plastic cover off.

 

[Mr Chuck Norris]

O2 sensor codes are not necessarily signs of bad O2 sensors themselves... The codes are often just symptoms of another issue in the EFI or emissions system. O2 sensors tend to gradually worsen with reduced MPGs or other drivability issues.

But at 240k... Might as well replace all 4 anyway. I rarely go more than 150k on stock sensors before swapping them out.

 

[Coin]

Inspect head gasket, very closely for signs of coolant leak (red crust trails).
Inspect for exhaust leak. From rear O2 forward is mainly what we're concerned with here today.
Top coolant properly. Watch close to see if level drops again. Make sure no clog in reservoir hose and it's cap, and that hose drops straight to bottom of reservoir.
Tune with new spark plugs, also Denso coil boot kit if they weren't replaced at last tune.
Make sure no vacuum leaks. Which last "tune", should have taken care of.
Do "Italian burns" (Drive at high RPM to supper heat CAT) Do this for 2 minutes at 4,000 RPM first time. Then drive normal for 7 to 10 minutes to cool CATs. If all went well (engine an feel okay) then drive at 4,800 RPM for 7 minutes, then normal. Then again for 10 minutes, then normal.) To cook gunk off CATs. It's like turning your oven to clean cycle.
If coolant level keeps dropping, with no leaks. Then a combustion gas test in coolant would be good idea. Also compression test. Also note condition of each spark plug and from which cylinder they came from. Coolant is a CAT killer. It has the effect of basically steam clean cylinders. Which spark plugs can give clues of.

Thanks! I do not idle for long periods, but do have often short trips. I'll look into the above list. The others shouldn't be a problem. I like the Italian burn idea!
I will also go ahead and swap out the sensors, since I have them.

 

[nissanh]

Does all 4 sensors use the same ground? How does the ground wire looks like at the battery and all main grounding locations? If rusted, clean those. Also visibly check for any damaged ground wires.

 

[nissanh]

If you haven't followed Ivan's auto diagnostics videos on you tube, here is one.

 

[Pucker5]

You could also clean the sensors

 

[Coin]

FYI, I replaced the rear o2 sensors, since I had them, cleared the codes and so far they have not returned. Fingers crossed that was it. I can tell you the old ones were filthy.