"Textured Soy Protein" (texturedsoyprotein)
03/21/2015 at 13:50 • Filed to: None
0
5|
"Textured Soy Protein" (texturedsoyprotein)
03/21/2015 at 13:50 • Filed to: None | 0
| 5 |
I'm pretty sure I need to get some new oxygen sensors for my Grand Cherokee. I've gotten 3 different check engine codes, none of which actually say "oxygen sensor," but they lead back to the oxygen sensors. I've got 4 of the damn things, but at least they're relatively cheap.
Codes I have pulled include:
P0172 - Bank 1 System Too Rich
P0175 - Bank 2 System Too Rich
P3497 - Cylinder Deactivation System
So yeah, those don't say "oxygen sensor." But the likely fixes for all of them have to do with the oxygen sensor(s). For example, I found !!!error: Indecipherable SUB-paragraph formatting!!! :
Oxygen sensors that have completely failed will usually indicate a rich condition and, if not replaced in a timely manner, could cause the overheating and failure of the Catalytic Converter on the affected side. For us Hemi guys, if it is rich enough at light throttle to change the fuel injection status to open loop, the MDS will also become inoperative.
MDS = Multi Displacement System, a.k.a. the Cylinder Deactivation System indicated with my P3497 code.
At first I thought I'd do these myself, but apparently they're kind of a pain to get at, especially the ones upstream of the catalysts. I have a good independent shop I go to, but they charge typical shop prices for parts.
In this case, a set of all 4 sensors is only about $95 from Amazon or RockAuto, but could easily cost double at a shop. So I'm thinking I'll order the sensors, then call the shop and ask if they can put them on for me. I feel a little bad cheaping out like that, but hey they still get their labor rate out of me.
UPDATE:
I downloaded a factory service manual (thanks, internet!) and found the section about these codes.
Only the upstream oxygen sensors, which are before the catalysts, are used in determining the air/fuel ratio, and if they go bad they can cause the too-rich warnings I got.
The cylinder deactivation system also looks at the Bank 2 upstream oxygen sensor. The section on cylinder deactivation doesn't mention the O2 sensor could be the cause of this code, but since I had those other codes related to the fuel mixture/O2 sensors, and the cylinder deactivation looks at the O2 sensor on Bank 2, that tells me it's probably related. Because otherwise the procedure to diagnose the cylinder deactivation solenoid involves taking off the intake manifold.
So...I'm gonna crawl under there later today and see just how tricky it is to get at those O2 sensors. I'll probably start with just the upstream ones for now, since they're the more likely culprits, and also likely more difficult to get at.
This is the exhaust removal diagram from the service manual, the fat cylinder things are the cats and the O2 sensors go in the bungs upstream of the cats.
brianbrannon
> Textured Soy Protein
03/21/2015 at 12:24 |
|
The ones down stream from the catalyst have no effect on how it runs they only monitor if they catalysts are working. Unlikely to have both oxygen sensors fail at the same time. It's probably something that effects both banks at once like a MAF dirty or vacuum leak or fuel pressure issue. I'm sure the shop will take your money to put new sensors in but you'll get no warranty if the light comes back on
505Turbeaux
> Textured Soy Protein
03/21/2015 at 12:46 |
|
WK strikes again
on my girls 3.7 it was just the O2 sensor wiring that needed to be mended
|
Textured Soy Protein
> 505Turbeaux
03/21/2015 at 13:03 |
|
I'm trying to get a copy of the service manual so I can see what exactly is involved in replacing the sensors. I just downloaded a PDF that I found on a forum, we'll see if it yields any useful information.
jariten1781
> Textured Soy Protein
03/21/2015 at 16:43 |
|
Grab an O2 sensor socket before even attempting to remove them. In my experience they're always frozen and very easy to round or strip using a wrench. Crows foot style has worked better for me than the long socket with the split side.
|
Textured Soy Protein
> jariten1781
03/23/2015 at 15:47 |
|
Good call. Some folks on the Jeep forums mentioned that it's easy enough to get at the sensor(s) with a socket, but getting at the connectors is a major pain. I ordered the sensors from Amazon, and am going to have this independent shop I've gone to before put them on.
I'm being a little cheap in that I'm not paying their marked-up parts prices or diagnostics costs, but I'm reasonably confident that I've got the right solution to the problem, and it's only my DD in the winter so I want to keep my costs down as much as possible.