Is there a specific problem (or set of problems) that will cause the CEL to flash and the ESP light to come on steady? This is on an '06 Liberty with 67K miles. The dealer claims to have found P0141 (O2 heater problem) and stored (?) P0300 (random misfire) codes, so they replaced the front bank 2 O2 sensor. Annoyed me both that they charged me $260 for a simple job that should have been covered under warranty, and that they did a half-ass job of diagnosing what could be a serious problem. Yesterday the KJ threw a P0430 (cat below efficiency) code, then this morning it was back to a flashing CEL and steady ESP during hard acceleration occasionally accompanied with a stutter. Weird thing is it it doesn't happen every time I accelerate, and it only happens at highway speeds.

The bad news is I had to replace the cats last year due to offroading damage, which means I suspect my chances of getting any of this covered under warranty is near nil. I used an Eastern Catalytic complete system, which had been working perfectly until recently. I think the next step for me is to replace the muffler, since it also has some trail damage and I suspect bits of broken cat lodged in it, then swap out the rear bank 2 O2 sensor with one of my spares.

If that doesn't do the trick, what's next?

Hmm... I guess I should clarify my question. Does anyone have the reference (or know where to find/buy it) for what sensor inputs would cause the flashing CEL with the steady ESP light? This has got me scratching my head because the CEL will cease flashing and turn off, while the ESP light will linger on for several seconds. Any additional information would be helpful, as while I'm waiting on parts to come in I'd like to come up with troubleshooting measures in case replacing the O2 sensors and exhaust doesn't do the trick.

Also, the ScanGauge II seems to be having some problems picking up the correct CEL code. It reads as finding a single stored code, but about half the time viewing the code displays a P0000, P0004, P2204, P2304, or weird hex code - the other half it seems to come up with (what I would guess to be) the correct code. I had similar issues when I crunched the bank 1 cat, which sent me on a bit of a wild goose chase. Is there a consumer code reader or code reading process that produces more reliable results on the Libby, or is it possible I've picked up a flaky ScanGauge II?

Classic cat failure systems.Replace the cats with OEM cats only,most aftermarket ones are junk after a few months.

Easy test,clear the codes then unhook the exhaust before the cats and take for a short test drive(no need to completely remove).The check engine light will turn on but after the short test drive(drive in the same condition that makes it act funny),the check enegine light will turn on for the test drive and that should only be 4 codes for the 4 O2 sensors and nothing more.If it acts normally then it is your cats that are bad,if it has the same issues it's in the engine.

Thanks Troy, and yeah, I'm afraid you're probably right - but I'm equally concerned that there's a contributing cause that would burn up the $spendy$ OEM cats in short order.

The flanges on the downpipe don't lend themselves easily to being disconnected without completely removing the catalytic converter pipe section. Can I disconnect and pull the front O2 sensors to bypass and test the cats, or will that just wreak so much havoc on the engine management system that a road test is meaningless/unsafe? Either way, it's a few miles from my garage until I can get to a highway where I can really test hard acceleration at speed, and I'm sure my ears will be ringing and burning by then!

More info - while monitoring engine data I noticed the flashing CEL and stuttering are only occurring when the PCM switches to Open Loop mode, which I should have realized given that the Libby's only having problems during highway acceleration (merging, passing, steep hills, etc). So... that means I'm only experiencing misfires once the input from the O2 sensors is no longer being used to monitor and control A/F ratios. Does this narrow down the possibilities for the cause of the problem or point to any particular culprits? In the meantime I'm still waiting on the new exhaust and sensors to come in (finally shipped yesterday), and hoping to get a chance to uncork the headers and test this weekend.

Just FYI, my current setup is:

'06 Liberty Renegade 4WD
3.7L, 42RLE auto, 67K miles
2.5" spring lift with conduit nut spacers in front and 2 spring isolators in back, OME struts and shocks
255/70R16 Goodyear SilentArmors on Moabs with owner installed new TPS sensors, stock 3.73 gears
Full Mopar skid plate set with aftermarket rock rails
Dealer installed tow package
Owner installed EVIC (60K miles), subwoofer and RBQ stereo (<1K miles)
Owner replaced trail damaged transmission pan (40K miles), front differential cover (45K miles), catalytic converters and rear O2 sensors (55K miles)
Since onset of issue I've changed oil, oil and air filters, PCV valve, plugs with fresh set of Autolite Double Platinums, front brake pad and rotors (unrelated vibrations while braking), run a can of Seafoam through gas tank, dealer replaced front bank 2 O2 sensor

Well, after nearly three months of travel, being snowed in, and delivery delays I installed the new OEM cats last weekend. Sure enough, that fixed the problem. I've still got a bit of valve tapping, which has me wondering about the odds of getting the valves looked at under the TSB for '05-'06 3.7L engines.