1997 Jeep Cherokee Exhaust System

MY301CAR

MEMBER
1997 JEEP CHEROKEE
6 CYL
AWD
AUTOMATIC
11,300 MILES

I had a new muffler installed last week, and now my "check engine" light came on. I had the code checked, and it reads "problem with oxygen sensor". I've never had this light come on before ever, and I'm wondering if they did something when they installed the new muffler.

1 Reply

CJ MEDEVAC

MECHANIC
11,004 POSTS

See my profile, I am unfamiliar with your particular rig. Some rigs have multiple sensors (see your newly aquired repair manual!)

Yours forever, troubleshooting, scheduled maintenence, stuff you did not know about your rig. Something to sorta go by when I explain things to you.

Can get one for your particular year and model, At local parts store for about $30 ! ! !

Some sensors are in the exaust manifolds, if you have a "V" type engine, 1 in each exaust manifold.

Some have a "downstream" sensor just past the Catylitic(sp) Converter. In all there may be several on your rig.

Here's the steps I would perform 1st, before FREAKING OUT on the "Muffler Man"

Did my code (coding is FREE at Autozone and Advance Auto) SPECIFY which O2 sensor was in trouble.(I am not a sales-pitch man)

Can you crawl under your rig and VISUALLY inspect the O2 sensor (if one, manuals usually show exact locations) nearest the muffler, for :

Cut out all together and GONE, wire dangling!

Connector disconnected OR broken wire (even on up the line)

Welding REALLY CLOSE, may have damaged it

Melted wire to it

Wire pinched in clamp/ other

Maybe the new muffler, was just a factor, And O2 sensor went bad on its own!

O2 sensor tells computer, What the "BURN RATIO" is leaving you engine (made that up, for classroom purposes!) The COMPUTER then decides how much or how little fuel is to be emmitted from your injectors (for efficiency). This is a Real World value that the O2 sensor gathers.

The O2 sensor only works when it is Hot, and Exaust flow over it.

You say, "How does my rig EVEN run when Cold?"

EZ-- The computer has PRESET values (takes the place of REAL INPUT values, UNTIL the O2 is "ONLINE") These PRESETS do not give you EFFICIENCY---Just make it RUN.

If your O2 sensor is "OFFLINE", the computer still keeps you running, but not to FULL POTENTIAL!

This is WHY you need to fix this NOW, whether it be "THEIR FAULT". OR. Maybe your MANUAL said to change it At 30,000 miles, 20th oil change, or when cats leave footprints on your hood.

Moral of my story: It needs to be fixed, cause it just went bad, maybe "You" failed in Scheduled Maintence (found in a Manual), they pulled the connnector loose, or it might be one, way up on your engine, Not even in your PRE-THOUGHT equation.

I like to help, not piss you off, otherwise I would not got to the Hunt and Peck effort I do!

Please let me Know your Turn-outage with your Jeep, For I am a JEEP GUY myself.

IT WAS AN "AWESOME-1 HOUR ANSWER, WASN'T IT?". Gotta do my chores now!

Love, Turddog