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O2 codes

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squeek

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All of a sudden I've popped four o2 codes. P0161, P0155, P0141, & P0135 with mil's on both lower. Both pre cats are gutted and a full main cat. Idle is 50 percent smooth 50 percent erratic. Could I be looking at a clogged cat?
 
squeek said:
All of a sudden I've popped four o2 codes. P0161, P0155, P0141, & P0135 with mil's on both lower. Both pre cats are gutted and a full main cat. Idle is 50 percent smooth 50 percent erratic. Could I be looking at a clogged cat?
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Might be. Might want to get a pressure test on the exhaust.

P0161 is the heated o2 sensor fault bank 2 sensor 2. Can be faulty injectors, air leaks or exhaust leaks.
P0155 is bank 2 sensor 1 fault. Can be an electrical short, which the ECM sees it switching too late, or not switching in the proper time.
P0141 is the same as P0161.
P0135 is the same as P0155.

I would do a injector check first, with the exhaust pressure check. It can be either a bad air/fuel delivery or the cat is clogged.
 
I'm running a full 3l also so I'm leaning towards a clogging cat.

Could a dirty air filter cause these symptoms.
 
squeek said:
I'm running a full 3l also so I'm leaning towards a clogging cat.

Could a dirty air filter cause these symptoms.
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Probably, but not likely enough to plug up a cat, if that happened. Are you using the stock Contour cat? It may be possible that over time, yes the OEM cat clogged with the 3 liter, they have enough trouble with the 2.5, Fords are known to plug cats easy since they run a bit richer than they should. I still would check the injectors though; I ended up replacing 1 of mine today because the injector was leaking internally as well as externally.

It may be possible too that the o2 sensors are failing as well. The codes indicate that, but at the same time, an improper fuel ratio also causes these issues. Without me putting the car on the dyno and doing a thorough check on it with the equipment I have access to, it is difficult to say exactly what is causing it. I have had the pesky cat inefficiency code and people tell me it is the cat, but I found other issues that cause these problems. Look into the simple stuff first.
 
No Title

It's the original 2.5 cat so it's been there awhile. There appears to be good flow coming out of the exhaust. I'm gonna grab a new filter and put her on in the engine bay.
 

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squeek said:
It's the original 2.5 cat so it's been there awhile. There appears to be good flow coming out of the exhaust. I'm gonna grab a new filter and put her on in the engine bay.
Click to expand...

If you have a scan tool, look at the readings on the o2 sensors on each bank. The primary o2 sensor should start working within 10 seconds of cold startup (as well as the downstream) and it should quickly flip between 1.3 to -1.6 at hot condition. If yours can graph the readings, it is much better to do that. The wave form should be consistent and have a nice steady wave to it.

Before you replace the cat, might want to yank the o2 sensors out and test those, possibly replacing all 4 of them. I would rather suggest that then looking into the cat first. If it has good flow, I would concentrate on other things first.
 
Yeah I just picked up a new filter and popped it in and no change. I have an obdii Bluetooth adapter and run torque. Well a friend had it at the moment. So I'll get it so I can get some readings.
 
Ok, lets start by really reading what the codes mean. As you can see they are all for the heater circuit for all four O2 sensors.

P0135 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0155 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
P0161 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

This normally happens when the fuse has popped for the O2 sensor heater circuit. Yes all for sensors are together for the heaters.

Also all mil-eliminators do is make the downstream sensor look like they are reading correctly. You have to have working O2 sensors and the heater circuit needs to work.

So before we run off going crazy about clogged cats, check the fuse.
 
Thanks for the advice Br. Looked in the book and couldn't find anything for the O2's but one I wasn't sure about listed as hego. Well checked it #13, 20 amp and it was popped. I'll be driving to work soon so I'll let you know.
 
X2 BrApple..................you fix the heater problem not chase engine issues there. Hego=heated exhaust gas oxygen, or the O2 sensor. A clogged cat will show at high load first, not idle. Cat can be poisoned to not work but not clogged as well.
 
squeek said:
Thanks for the advice Br. Looked in the book and couldn't find anything for the O2's but one I wasn't sure about listed as hego. Well checked it #13, 20 amp and it was popped. I'll be driving to work soon so I'll let you know.
Click to expand...

As long as the fuse doesn't blow again you should be good to go. If it does blow again then you will need to trace the O2 sensor wiring to make sure it hasn't become grounded somewhere. Hopefully it isn't a wiring harness issue either.
 
Hi, Can anyone confirm where Bank 2, Sensor 1 is located on the 1999 Contour SE 2.5L V6 VIN L?
The reason I asked is that I had a P0155 error, and I am still throwing the code after resetting the ECU a few times.

Also does anyone have a test procedure for the sensor and what all triggers this code. No other codes are currently showing or pending. Thanks.
 
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