HELP: Repair issues after CAT's were stolen.

Hello All,

Looking for some help on my 2014 SR5 Crewmax (5.7L). The truck has 128,000 miles, and doesn't have any mechanical or electrical upgrades.

The CAT's were stolen off of my truck a few weeks ago. They cut the wires on the downstream O2 sensors between the connector and the sensor and the CAT's were cut between the flanges, so it seemed like a pretty easy replacement job.

Attempt 1:
I ordered replacement parts on Amazon (direct-fit Magnaflow CAT's and Denso O2 Sensors). I made sure the mfg part numbers on the listing matched up to Autozone's website as well as the manufacturers website. I installed everything and drove over 100 miles, but I was still getting the P0137 code, which points to the driver side, downstream O2 sensor.
Parts List:

• Denso 234-4926: O2 Sensor (Downstream, Passenger)
• Denso 234-4927: O2 Sensor (Downstream, Driver)
• MagnaFlow HM Grade Federal/EPA Compliant Direct-Fit Catalytic Converter 93458
• MagnaFlow OEM Grade Federal/EPA Compliant Direct-Fit Catalytic Converter 49935

Attempt 2:
I thought I may have received some bad O2 sensors from Amazon, so I bought a pair of Bosch sensors from Autozone. After installing the Bosch downstream sensors and driving 100 miles, I'm getting the following codes:

• P0607 - Control Module Performance
• P0137 - O2 Circuit Low Voltage (Bank 1, Sensor 2)
• P0138 - O2 Circuit High Voltage (Bank 1, Sensor 2)

Parts List:

• Bosch 13354: O2 Sensor (Downstream, Passenger)
• Bosch 15672: O2 Sensor (Downstream, Driver)

Any suggestions for next steps?
Is it likely that a faulty new catalytic converter is causing this?
Also, I am still using the original upstream O2 sensors. Do the error codes hint that they need to be replaced or are not compatible with the Bosch downstream sensors?

 

Sorry if this is a dumb question, but did you clear the code after replacing everything? If not, maybe 100 miles wasn't enough to clear the code. I think it needs a mix of driving types before it clears it. If you have OBDII scanner it should tell you if all of the emission checks are complete.

Also Toyotas don't play nice with Bosch O2 sensors so I'd go back to the denso.

 

I pulled the ECU fuses and disconnected the battery after both repair attempts. I believe that should clear the code, but I could be wrong.
When I reconnected everything and started the truck, the Check Engine light was off for a while, but came back on.
Both times, I had the codes pulled at AutoZone, so I'm not sure which type of scanner they use.

I can put the Denso's back on and should be able to return the Bosch's to Autozone.

 

Maybe it’s a stupid question, but are there specific fuses for the O2 sensors. Maybe it’s possible when they cut them, it blew a fuse. Or maybe they tugged on the wires and pulled the connector too hard. Make sure all the pins are inserted. It’s possible you got a bunk Denso as well. I wish I could tell you how to test the new one to confirm it is a good part.

 

I'm guessing that you didn't let your insurance company pay for the repairs?

 

Yes, I filed an insurance claim. The repair seemed like it would be easy, so I had them issue me a check for the repairs. Everything seems to be running fine, but I haven't been able to clear the codes.

Any idea which fuse is for the O2 sensors?

 

Doesn’t disconnecting the battery do the same, clearing the codes? Reason I ask, is that he says it takes about 100 miles before the light comes back on. So to me that says it was reset with the battery disconnect. But the code pops back up because it isn’t fixed. Just spitballing

 

I said take me as I am
'Cause you might enjoy some madness for a while.

 

On other past vehicles (Honda and Jeep) I have found that non-OEM O2 sensors never seemed to work right and gave me codes. Paying a bit more for ones from the dealer always seemed to work. Not sure how sensitive Toyota’s are but it might be worth looking into.

 

I believe the Denso sensors are OE. I'm about to put them back on and return the Bosch sensors to AutoZone.

I'm still unsure if the fuses could be causing the P0607 code. Does anyone know which fuse is linked to the O2 sensors? I'm not able to tell by the diagram on the cover.

 

This may be your problem.

 

What am I missing here, the brand or the direct for quote?

 

P0607 is the standard OBD-II trouble code for an issue with the engine control module (ECM). The code suggests that the ECM is experiencing problems, such as power failure or memory loss, and thus may not be able to do its job properly.

https://www.obd-codes.com/p0607

 

I believe the direct-fit magnaflow CAT's are the best option for aftermarket, but I'm not too familiar with that. I didn't order to OEM CAT's because they are about 3 times the cost.

I'm not sure what you mean in your message. Are you hinting that I might have received a bad Magnaflow CAT? Or are Magnaflow CAT's not good in general?

 

@BaldEagle2006
https://retrofitsupplysource.com/products/o2-oxygen-sensor-extender-spacer-extension-m18x1-5-hho-bung-1-75-usa-02-cel-fix?variant=39293698769078&currency=USD&gclid=EAIaIQobChMIgbqRvcS18AIVrSCtBh2XjAFsEAQYAiABEgKrjfD_BwE

I wonder if you could try something like this. This isn’t an actual part for your truck, you would have to look up the proper part number. But it’s cheap and will space your O2 sensor away from the exhaust gases and lower your O2 reading. Designed for high flow cats and straight pipe jobs. I think another option is completely plugging the O2 sensor bung and leaving the sensor zip tied up in a frame rail. I’ve only heard the theory and never actually looked any deeper than that though.

 

Lots of good suggestions here.... things that I would check (in some general order, but can skip around):

• Denso O2 sensors should be same as OEM, assuming you didn't get hosed by a counterfeit via Amazon. I'd go back to those and return the Bosch ones.
• If I remember correctly, some O2 codes only set after so many cycles or miles driven. (Perhaps 100 mi is the magic #?). So even if you do nothing, reset the code, it will stay off for a period of time until computer decides it's still bad for greater than the # of cycles or miles as the threshold.
• Double check all connectors as someone else mentioned to make sure no other wire damage or pin damage.
• A good OBD2 scanner should be able to show you the O2 "stats" while engine is running (may indicate voltage or "cross counts". Basically, a constant value = something wrong). Can see if you can rent one out for a day at a local auto parts store.
• Also, I'd check to make sure you don't have any exhaust leaks upstream of the sensor after replacing the converters. That can also cause O2 sensor reading issues.
• You should be able to check to see if the converter is "working" if you have an infrared temp gun... There should be some test procedures in Youtube that show how to get them to "light off" and then check the temperature of the pipe before and after the converter to make sure it's working.
• A/F sensors do get lazy after 80-100K miles. They may need replaced, but I wouldn't think that they would cause the immediate situation since you had 0 symptoms prior to the vandalism. I'd confirm everything else before heading down that path.

If all else fails, maybe take it in and have insurance pay the full bill for 100% factory cats / parts?

 

I want to say the computer has a mileage check in the code to stop people from doing exhaust swap and then running to the DEQ for a check. Check for mileage requirement, might be about 80 miles. Clear codes and drive for a few days.

 

Here's how you fix the problem step-by-step:
1. Return cheap aftermarket parts.
2. Order parts from Toyota.

Problem solved. If it was an insurance claim, insist on the OE replacement cost. That's what was on your truck before the loss, that's what you want on the truck after the loss.

Toyota doesn't charge four times the cost of the aftermarket replacements just because they're greedy.

 

Thanks everyone for the tips and suggestions!
I put the Denso sensors back on and returned the Bosch sensors to AutoZone. I unplugged the battery to reset the Check Engine light, but it came back on after about 15 miles. The AutoZone scanner gave code P0137. I'm going to drive to about 100 miles and rescan. If nothing changes, I'm going to try another Denso sensor from AutoZone.

I'll report back. In the meantime, feel free to keep sending suggestions.

 

I took my truck in for inspection a couple of weeks ago. Frisco Automotive and Transmission had a 2016 Tundra sitting there when I arrived. I spoke with the owner. He had his CATs stolen and Frisco Automotive replaced them with aftermarket CATs. They could not clear the codes either. The owner of the shop said after doing research that he would have to put OEM CATs back on because for some reason they are the only ones that will not trip a fault code. He also said it was odd because he used aftermarket CATs on a 2012 and everything was fine.

The shop's phone number is 972 335 9823 if you want to verify it with them. He might be able to give you more information regarding it.
https://friscoauto.com/

 

I still suggest trying the bung extensions for the O2 sensors before going to an OEM cat, although I’m sure that would fix it.

 

See post #21.

 

Did you replace the cut harness for the O2 sensors or splice them ? I'm not familiar with Toyota specs but if you spliced them there might be too much resistance and causing codes. When signals are measured in mAh it doesn't take much.

Just a thought

 

The harness wasn't cut. They cut the wire that is connected to the O2 sensor. It's a 10" wire that goes to a connector. I just had to disconnect what was left of the wire and hook up the new O2 sensor. No splicing or anything.

I've considered that they could have tugged on the CAT with the O2 sensor still connected, which could lead to a short somewhere in the wiring harness. That is way above my level of expertise and sounds like a costly repair, so I'm trying to rule out everything else before I go down that road.

 

Had the same problem with a bad cat. Tried going with aftermarket, still got CEL. Changed to OEM Cat and problem solved. From my past experience, Toyota’s do not like aftermarket cats.

 

Since the magna-flow is aftermarket, and possibly high-flow? You may try a fouler or oxygen sensor extender.

Here's a quote from my build thread when I put one on my Downstream sensor. These are intended for high-flow cats/off road applications. Ky doesn't do emissions testing so this flies here. I'm not sure how it is where ever you are.

I'm not sure if the 5.7L exhaust sensors screw in, or bolt on like mine, but I have a 90° fouler if you want it. No clue if it fits or not, but you can have it for cost of shipping.


Samsung charge base for scale.

 

Did you ever get your issue fixed? I'm having the same issues on mine after all 4 of my cats were stolen.

As for those advising to use OEM cats - great advice! Only problem is that OEM cats are back-ordered for who knows how long - there are none available anywhere for sale in all of North America. So I got put on a waiting list. But as far as waiting lists go, I have to wait until dealer lots get their replacement cats as they're first in line. Yes, dealer lots are also getting hit bad by cat thieves.

Anyway, after months of waiting (with my Tundra parked for most of that time), I eventually gave in and went with Magnaflow aftermarket cats (which according to three shops I spoke with are supposedly of higher quality and more expensive than most other aftermarket cats). I did use factory Toyota OEM O2 sensors (at least the O2 sensors are still available). But my check engine light stubbornly remains.

 

Some time has passed.... Updates?

 

Completely forgot about this thread til now. Another shop discovered the cat thieves cut the fuel line and EVAP purge valve line. That’s what was causing the check engine light to come on. It was an additional $2K or so in damage, but luckily insurance reimbursed me.

I no longer have a continuous check engine light, but it still randomly comes on every so often. Each time it does, it’s the same code - “inefficient cat” in bank 2, or something like that. The ECM is just being picky about one of the Magnaflow cats (forget which side is Bank 2). I just clear the code and continue on my way. I did pass annual emissions testing, though, so that’s good.

 

That is good and bad. Bad about the light still coming on. Passing emissions is good.
I got them on order. If all goes well I have an update soon. I hope.