Hi Everyone,

I'm seeking some advice, please. I've experienced several O2 sensor failures, indicated by the "Emission Service Required" warning, on my 2013 V8V with approximately 32,000 miles on it. I've replaced the following sensors with new ones:

- Bank A - Upstream and Downstream
- Bank B - Upstream

However, I'm still getting a persistent P0137 code that reappears every time I start the car from cold. If I clear the code and start the car when it's warm/hot, the code doesn't return until the next cold start. I'm almost certain the sensor and its wiring are fine. When monitored using my Launch 909x, the voltage readings appear spot on (and compare the other sensors in the other bank). After extensive fault-finding this weekend, I'm confident that the issue isn't with the sensor or wiring. The engine runs a little bit rough when cold and occasionally misfires when hot and idling.

I've read that the P0137 code might be related to a weak battery, so I've replaced it with a new one (which I believe was on its way out anyway). Here are the issues I'm encountering:

• The P0137 code persists on cold starts.
  • Error: "Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 2)"
  • The car occasionally misfires when idling, whether hot or cold. You can feel it and there is a "pop" noise.
  • When the code is present - it feels a little sluggish and clunky to drive.
• I’m confident that all the sensors are functioning correctly, including Bank A - Sensor 2 (where the P0137 code originates).
• To the best of my testing, there are no air leaks on the inlet side.
• After swapping the battery, I needed to perform the "misfire correction procedure," which I've attempted but haven't succeeded in completing.
  • My OBD tool allows me to monitor for misfires, but I can't do so until the procedure is successfully completed.

My questions are:

• Has anyone managed to resolve the P0137 error after extensive troubleshooting?
• Will the misfire correction procedure sort itself out with regular driving? I've found mixed information online regarding this.
• Could a faulty plug or ignition pack be causing the misfires and the subsequent error code?

Thanks in advance for your help.

Best regards,
L.

 

I have 13 V8 that every now & then will get P0137 code too, If I clear it'll go away for few months before I see it again, but I don't drive much. I don't feel my car has any misfire, runs good cold or warm. I have all new O2 sensor, planning to to replace them all at some point. if you feel you have misfire, I'd start with new plugs 32k miles that could solve misfire issue after that see if that fixes p0137.

 

Thanks JB,

I was just going back through the service history and I can see the plugs were changed in Aug 2021, and they have done about 11k since. No mention of the coil packs being changed though.

I think I will change everything and give it a full service while I am at it. Struggling to find plugs at a sensible price at the moment - not sure why that is.

Appreciate the feedback JB - keen to see if anyone else has had similar issues.

 

2010.5 and up retain misfire corrections with battery disconnect. So you should have them as the only way is to clear via dealer AMDS. Have you tried any fuel additives or cleaners?

 

Thanks for coming back to me

No I haven't yet. Happy to give it a go if you have had some luck with them in the past? I did think about trying a Cat. cleaner.

 

Just thought I would give an update on my post.

I tried a Cat. cleaner and then completed a 280mile round trip, at motorway speeds. The error still persisted when started from cold.

I decided to investigate the "popping" noise and found that it was actually the butterfly valve in the throttle body, which was sticking and needed a service. As per the post below:

https://www.pistonheads.com/gassing/...tching%20stops.

Cleaning it has certainly stopped the "popping" noise. The code however is still there on a cold start. Below is a picture of the car idling (warm) showing the voltages of Bank 1 sensor 2 and Bank 2 sensor 2 for comparison. Does these look normal?

Thanks in advance.

 

They definitely don't match. Seeing how you get a fault every cold start I would re-evaluate your bank 1 sensor 2 wiring and/or replace it again. I have seen new sensors fail soon after replacing.

 

Thank you for coming back to me.

I was literally just looking at the scan tool again and wondering what the chances of a new sensor being faulty were. Not impossible I guess?

Ill order another one up and swap it out.

 

My understanding is the upstream O2 sensors are the ones that control fueling and the ones after the cat are really just to monitor emissions. It seems a bad #2 O2 sensor wouldn't cause misfires.

If you google "o2 sensor graph" or something like that you'll get a lot of info on what the O2 graph should look like. The #1 sensor should fluctuate up and down while the #2 sensor should remain fairly steady. People did say a lot of the time a standard scanner won't be fast enough to see the changes and you need a scope.

 

Thanks David.

I believe the misfires are down to it needing a good service. Pugs are packs are on the way. Plugs are 3 years old, no idea when (or if) the packs were changed last.

I have just done some testing - I am now confident it is faulty sensor. Which is annoying as it is a brand new OEM.

I used the connector from the old sensor and stripped it back, then shorted the signal wire. I was immediately able to see the input on my scanner ramp up and down (seen below). Before cutting up the old sensor, I connected it to the car and sprayed some isopropyl on it, which also gave me a reading (0 - 0.5v). I will order up another one, replace it, and then put an update on here.

 

Downstream O2 sensors do not control fueling (as the upstream sensors do). Downstreams cannot as the exhaust gasses that pass through the CATs are completely altered and do not provide what the EMS needs to maintain fuel trims.

If this were mine, I wouldn't be looking at a correlation between a P0137 and misfires; instead, work on the misfire corrections. If misfires exist they should be producing separate P-codes - Any of combination of a P0300 (random misfires) and/or any list of P0301 through P0308s. It shouldn't take the correction for the EMS to ID actual misfires.

On the downstream O2 sensor, and on a different car, my wife's F-Pace, I had a failed downstream sensor (B1) continue to fail and produce a CEL every few starts (as on startups is when the ECU runs diagnostics for sensor presence and functionality). I replaced the sensor and it continued to produce CELs on startups. I then chose a different aftermarket O2 sensor which solved the problem permanently (over a year now).

Not sure any of this will help you, but hopefully give more insight.

 

Thanks, BWings. That does help.

I have a service kit on the way, and I’m hoping it will resolve the misfires. The misfire is subtle, but I do notice it. There are no codes other than P0137 and P1000, which appear after I clear the codes. P1000 vanishes once I drive a little way (which I understand is normal, it is a self-diagnostic code).

I know the downstream sensors are meant to asses the performance of the Catalysts. I've seen no error codes for them P0420 (or similar).

I’ve just ordered two more Denso sensors (DOX-1716). I haven’t yet changed the one on Bank 2, but I’m guessing it will probably fail soon given that the other three already have. Hoping that I was just unlucky having a dead 02 sensor delivered (I wouldn't be the first).

Shorting the sensor signal wire did give me an instant voltage spike, so I guess that rules out the cabling from the connector backwards. If the new sensor doesn't resolve the problem, I will resolve the misfire next, then if I still have an issue, I will pressure test the the Cat. then remove it if needs be. I am really hoping that is a rabbit hole I dont have to go down....

 

Hi Everyone,

I wanted to provide a quick update. During some additional testing yesterday, I accidentally shorted my test wire on the downstream O2 sensor on Bank 1, which resulted in blowing the 15-amp fuse in the engine bay.

While replacing the fuse and having my tester out, I decided to check all the other fuses in the box. To my surprise, I discovered two other blown fuses that must have been faulty before I purchased the car. They were:

F26 - Headlamp Wash Pump 20A
F31 - Heated Front Screen 40A

I've since discovered that the manual is incorrect. Fuse F31 is actually for the "Secondary Air Pump."

After replacing the fuses, I started the car (which didn't sound great) and drove about a quarter of a mile before the car entered limp mode. I managed to get it back home and ran a scan, which returned the code "P2258":

P2258 - Secondary Air Injection System Control A Circuit High.

I cleared the code, started the car again, but the same issue occurred, along with the "Urgent Emissions Service" message on the dash and limp mode. Clearing the code and removing the fuse in F31 stopped the code from reappearing. I suspect this fuse was blown before I bought the car, as it doesn’t show up on any scans.

This situation makes a lot of sense, as I've been seeing the P0137 code only when the car is cold—precisely when the Secondary Air Pump should be running. It also explains why the car has been running roughly when cold. Once the engine is warm, the problems disappear.

In my research, I've come across mentions of a relay installed under the "Jump Start" bracket on the left side of the engine bay (as you stand in front of it). I don’t have one, and I can only assume that at some point, AM replaced the relay with a 40-amp fuse. Could anyone confirm this?

I've found very few discussions about the Secondary Air Pump, which is located beneath the air intake. Does anyone have experience with this? Is there anything I should be aware of before removing the air intake manifold to inspect it?

Also fuse "F26 - Headlamp Wash Pump 20A" seems to do very little, but I dont think that is relevant.

Thanks in advance,

 

Strange you weren't getting a P0410-12 codes for that. I've seen rodent damage to wiring in that area as it makes for a good nesting spot.

 

I thought the same. Really odd that I was getting nothing at all. Wish I had as it would have saved me some time.

I was browsing some pictures of engine bays last night and I noticed that cars beyond MY2010/2011 all seem to be missing the relay for the pump. Guess AM did change the setup a little.

Just hoping that someone has some test advice before I start removing the air intake manifold.