JIMO

Hi gang, new to the forum.
I figured that I would post this as it may help someone someday. I just bought my second XJ with 193xxx miles. I bought it as a fixer upper. It needed a power steering pump and had a check engine light on. The seller said it was an evap leak code and had been driving it a while. I did the steering pump and then took it for a drive.
Noticed a few things: NO OVERDRIVE, NO BACK-UP LIGHTS AND PERIODS OF MISFIRING, usually after idling. So, I plugged in the scanner........14 codes!!! Thinking to myself, what did i just buy?

First list of codes:
po300 - random misfire
po132 - o2 sensor voltage high 1/1
po443 - purge valve circuit
po301 - cyl 1 miss
po302 - cyl 2 miss
po303 - cyl 3 miss
po161 - o2 sensor heater circuit
po138 - o2 sensor voltage high 1/2
po158 - o2 sensor voltage high 2/2
po455 - evap emiss gross leak
po130 - o2 sensor circuit 1/1
po1494 - evap leak detection pump switch condition
po136 - o2 sensor circuit 1/2
po705 - Transmission range sensor

I cleared the codes and this is what came back immediately:
po705
And then after one drive:
po136, po130, po443, po705
So being a bit old school and new to troubleshooting obd2 stuff I was a bit lost....so 2 days searching on the internet and found (nothing more than B/U lamps in the owner's manual) that all those recent 4 codes have something in common:
Fuse #10...TRS, o2 sensor heater relays, Back up lamps, Purge duty circuit, (and more rad fan relay a/c clutch relay)

Fuse 10 in the pass kick panel was blown. I replaced it and took a drive. Wow back up lights and overdrive and runs smooth!! BUT that lasted for 3 days until the fuse blew again. I went looking for a bad harness visually. YEE HA found it at the transmission dipstick tube, the trans harness from below came up and crossed across the top of the tube. The wire by the plug was rubbed through (in the engine compartment). I sealed the rub through and cleared the codes.

After one week I got a check engine light again....po161 and po455.
I cleared again, and again after one week of short trips and two 45 min trips the same po161 and po455. I thought ok, now we are narrowing it down. It was running great!
I visually inspected the evap system for the 455 code and underneath by the e-brake adjuster, one of the hard plastic vent lines was broke. I repaired that. The code disappeared after a day.
For the po161 code which is the o2 bank 2 sensor 2 heater circuit I searched the net and found the location of the sensor and read and found electrical diagrams for the heater circuit. I troubleshooted the relay, wire harness, ohmed the o2 heater directly (6 ohms), and did current draw (about 2 amps), it all seemed ok. But on a whim, I went ahead and changed the o2 sensor 2/2. po161 went away immediately. That in itself was a pain as the sensor was seized in. Heat got it out but the threads were galled. After more internet, I learned the correct thread size....18mm, the same as a spark plug thread chaser...$6.99 at the parts store.

All this took place over 2 of the coldest months and now the system has run all its monitors and I have a "green" light, ready for inspection.

Good Luck,
Jim

CCKen

VERY Good Work!

Stick around and help others that cry about codes.

Rogue4x4

EXCELLENT first post. Welcome to the forum.

salad

Nice!!!

Welcome! You will fit in well!

tyguy

Myself being new to the whole DIY thing, I learned a lot reading your post. Though thankfully my cherokee doesn't have any codes at the moment.

I can only hope when the time comes my detective skills are as good as yours!

JIMO

Thank you! Alot of what you had posted came in handy, especially some wiring diagrams and fuse block info. I am not an authority on this stuff, but will help where I can.
Jim

JIMO

I could not have done it without the help of others on here and lots of luck.
Jim

JIMO

Thanks guys for the welcomes!!!

I do have an update on this;
No M.I.L. light, but I decided to connect the scanner for the heck of it and got a pending code...po456 - small evap leak. This is after a week and a half of misc. driving. I guess after the large leak passed, the system then runs the medium and then the small leak check...if I have that correct.
The other 2000 xj with 115,xxx miles that I drive has that same code on and off (seems only during cold months). I have not looked into it. Someone that I had talked to said he took his purge valve apart and somehow cleaned it and his went away. I may start there along with another visual. As of yet, I have no idea if it is intermittent on the 193,xxx mile XJ. If I find something I will report back. Not many definitive answers for this one out there.
Jim

CCKen

I take it you have an LDP.

Sometimes a gas cap seal will cause a 'small leak'. Try a new cap.

JIMO

LDP? Is that the leak detection pump? Don't all of the 97-01 xj's have them?

I will keep the gas cap in mind, thanks.....actually it is the cap from my other 2000xj, you know the one with the same intermittent problem? I swapped it when trouble shooting the large evap leak. Hmmmm...

Upate: no MIL light but plugged in the scanner today....pending code gone!! Good to go as of now.
Jim

JIMO

Well it has been several months since I have updated my post here, and the intermittent po456 (small evap leak) became a steady check engine light. I finally had some ambition to look into it. Got under the 2000 XJ after looking around under the hood. My eyes were drawn to a short section of rusty vent line between the fuel tank and charcoal canister. I carefully removed the steel line, to check it out of the Jeep. As I blew into it air came out in the middle. So check your steel line fastened to the floor over the rear axle area if you have a later XJ. I replaced the line with some I had. After a few days of driving, the check engine light went out on its own.

Good Luck

centuryhouse

Thanks for that info!

I hope I never need to use it

RRXJeeper71

I was having same CEL 456 (small EVAP leak)
MY trusted mechanic diaganosed a bad piece of tube and bad fuel cap
Code went away and stayed away for over 1 month
New CEL code 455, came on yesterday(large EVAP leak)
I will tell mechanic about what i have read on forums
I will post update soon

Weather in Austin Tx has been warm, but gets cold on occasion

JIMO

Keep us posted...Thanks

FYI: I also at one point had the engine kick back on a start and blew a hose off the intake that created a large leak....just sayin...maybe a peak under the hood.
Good Luck

RRXJeeper71

my trusted mechanic ran a second and third smoke test through Evap system:
he found two piece of old rubber transition pieces that were cracked and worn
They were located under cargo area and the clamps were turned up to floorboard. Hard to spot cracks. replaced them and ran fourth smoke test!!! Started up truck next morning, cold mornings here and all is good now!
Check your rubber pieces in between hard steel lines and plastic lines under vehicle