Code help please

[mavrick1903]

2007 v8. DT Headers, first cats are high flow (Gibson?) second are still stock. Gibson cat back exhaust.

Following codes being produced. No runability problems, I can reset and it's fine. a day or two later, I get same/new codes.

P0051 H02S Heater Control Circuit Low Bank 2 Sensor 1
P0158 o2 Sensor Circuit High Voltage Bank 2 Sensor 2
P2196 o2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1
P2198 o2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1
P0156 o2 Sensor Circuit Bank 2 Sensor 2


Any thoughts before I take it to a local indy shop?

TIA.

 

[mavrick1903]

I don’t know how I locked the damn thread. Still looking for input.


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[waypoint]

I see you have headers on it, get under there and check for burned/melted wiring in all 4 O2 sensor harnesses.

Next, remove the EFI and EFI-2 fuses and test continuity with a meter (looking for infinity reading).

 

[mavrick1903]

Wires all look good. Didn’t find any bad fuses either.

Any other thoughts?


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[waypoint]

The only commonality in the shop manual diagnostics among the error codes you listed is open or short in the O2 sensor circuit(s), e.g.

• Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
• Open in Air Fuel Ratio (A/F) sensor heater circuit

If you're not seeing wiring harness damage, it's likely time to take it to a shop.

 

[BlackWorksInc]

Bank 2 Sensor 1 Oxygen sensor is probably dead or dying, unless the heater circuit to the sensor got damaged.

The other DTCs could be a lot of things, including the ECM not liking your exhaust modifications. Would probably need a shop to diagnose it further.

 

[aemravan]

You don't get anything after clearing the codes for a day or two because the system needs to go through the initialization process to verify each system. The O2 system takes a while depending on what sort of driving you're doing so that is why you end up kicking out the same codes.

Are the cats/exhaust a recent upgrade? Or have these been on the car for a while? It would be helpful to know when you developed the issues.

If you had the components on your car for a while and are just now throwing codes, its more than likely failing O2 sensors. If you just upgraded I would lean towards a combination of sensors starting to go, and not reading like they expect with a higher flow rate.

You're not seeing any drivability issues because the ecu will just trim the fuel on the rich side to keep you from melting stuff.

 

[mavrick1903]

The exhaust was on before the headers. The headders were done 11/2018, maybe 2017. Codes are much more recent.

Is the general consensus that replacing the O2 sensors would resolve the codes?

Any suggestions on which O2 sensors are best?


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[Brutalguyracing]

What code reader are u using

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[mavrick1903]

Carista. Bluetooth.


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[waypoint]

The codes you're reading indicate all 4 sensors have failed. The odds of all 4 dying simultaneously are slim.

Good experiments would be:

1.) Swap the A/F HEATER relay with another one in the under-hood fuse panel. Plenty of the same relay part# in there, pick one you know works and you can easily tell if it stops working after putting the existing A/F HEATER relay in its place. I'd consider the EFI relay right next to it (assuming yours is same as my '07), if that relay fails it won't start or run. Remove these carefully, gentle wiggle while lifting so you don't bend or stretch the pins.

edit: 2.) Replace the A/F HTR fuse with a new one.

3.) Replace one sensor (I'd do one of the upstream lambda sensors), clearing the codes, and seeing if the error code for that bank & sensor stays gone.

Let us know what you find. Test 1 is simple and fast, if it won't run then you found your culprit...sensors without active heating won't read correctly while the engine is warming up.

 

[mavrick1903]

Ok, swapped the relays as suggested. Engine fires right up, like always. So it’s not the relay.

How bad is the O2 sensor to replace? Special socket set or open end wrench?

Is there a sensor to look for or avoid?


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[waypoint]

Ok, swapped the relays as suggested. Engine fires right up, like always. So it’s not the relay.

How bad is the O2 sensor to replace? Special socket set or open end wrench?

Based on these questions, I'd say take it to a shop.

Is there a sensor to look for or avoid?

Stick with Denso sensors, avoid aftermarket ones.

 

[mavrick1903]

It’s an access issue. One on Jack stands in the driveway. Trying to determine how much removal is required to access. I can roll under and see the O2 sensor on question. Not sure what it takes to get it out.


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[mavrick1903]

I should also state I’ve got the SlyFox(?) secondary air pump delete installed for several years now.


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[waypoint]

It’s an access issue. One on Jack stands in the driveway. Trying to determine how much removal is required to access. I can roll under and see the O2 sensor on question. Not sure what it takes to get it out.

Soak it at the base with Liquid Wrench, or Kroil, for at least a day prior to removal. Buy an O2 sensor socket in 1/2" drive and use a long breaker bar to break it loose. Back it out slightly, spray the base with more Liquid Wrench or whatever penetrating oil, turn it back in, then back it out further...and repeat. This minimizes risk of buggering up the threads in the exhaust pipe bung.

The O2 sensor socket has a cutout on the side to pass the sensor's wiring through.

 

[Brutalguyracing]

Also do it while hot

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