What does this CEL mean?

Keith1138

Keith1138

Well-Known Member
Joined
Nov 18, 2015
Location
Harrisburg NC
So the jeep decide to let her light shine tonight attached is a picture of the code. I went and made sure they were plugged in. I'm hoping that fixes. Anything else could throw this code?
4437820ea17117e271a8c290b9713d18.jpg


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Could be sensors or cat itself. The computer is not seeing enough of a difference between the upstream and downstream sensors. Either a sensor is bad, or the cat itself is bad...
 
Will your code rider show o2 voltage if so that would cancel a bad o2 if it's within spec

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LBarr2002 said:
Could be sensors or cat itself. The computer is not seeing enough of a difference between the upstream and downstream sensors. Either a sensor is bad, or the cat itself is bad...
Click to expand...
How would I tell which sensor or if it's the cat

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I would bet on bad cat. Sure signs would be the obvious, sulfer smell, rattle in the cat, lost power....
 
So I don't have any smell or rattle that I can detect. I looked at the voltage at idle for the bank 1 sensor 1 and 2 they both stay between .1 and .9 and when one drops or rises the other follows behind it.

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Keith Odom said:
How would I tell which sensor or if it's the cat

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Click to expand...

My scanner didn't have a fast enough refresh rate to really tell what was going on. I replaced both sensors ($50) and the code came back. Then my cousin traded her patriot because the cat is made into the exhaust header at its an $800 part and the car was worth like $1,200...
 
LBarr2002 said:
My scanner didn't have a fast enough refresh rate to really tell what was going on. I replaced both sensors ($50) and the code came back. Then my cousin traded her patriot because the cat is made into the exhaust header at its an $800 part and the car was worth like $1,200...
Click to expand...

[Insert Patriot joke here]
 
The PCM is seeing similar signals between the upstream and downstream oxygen sensors, thus it sets a cat efficiency code.
You need to monitor the downstream oxygen sensor signal. It should be steady with very little change at all. Generally they stay right at 0.6v at operating temperature. If its voltage is moving around like the upstream signal does, the cat is bad.
 
Jody Treadway said:
The PCM is seeing similar signals between the upstream and downstream oxygen sensors, thus it sets a cat efficiency code.
You need to monitor the downstream oxygen sensor signal. It should be steady with very little change at all. Generally they stay right at 0.6v at operating temperature. If its voltage is moving around like the upstream signal does, the cat is bad.
Click to expand...
Thank you that is really helpful I will read it tomorrow at operating temp.

Will it hurt anything driving around with a possible bad o2 sensor or cat?

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I'd guess the rear o2 sensor is bad but being your jeep killed a motor, it very well could have messed a cat up. Won't hurt anything assuming you haven't noticed any power loss.

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After looking at the sensors using the torque pro app and a bluetooth connector that seemed to have a fairly fast refresh rate because the numbers where changing every second. The 1st sensor number would fall and go up then the second was changing just as fast. I pulled up the sensors for bank 2 also the first number seemed to be changing allot then the second sensor was changing with it but not nearly as much with bank one. Bank one sensor two was almost matching bank one senor 2. I'm thinking this is a bad cat. and the second one is about to go out also. The way my emissions is set up is that my 6 headers are split into groups of three and each one has a cat then the two pipes come together right past the cats then go through another one then the muffler. I'm considering ordering this 2000 JEEP CHEROKEE Walker Direct Fit Catalytic Converters 52304 because i could install that here at school verses cutting out the old cats and welding a new one in. Any suggestions or confirmations would be appreciated.
 
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