Jeepney

Hi New to forum my name is Joe ..I have a 2001 XJ all stock all maintenance kept up according to owners manual...I have 175,000 miles on it..has never given me a problem till...
check engine light came on 2 weeks ago..has been running fine. The light went off...yesterday it came back on again..of course i ignored it..drove 100miles made a quick stop...jeep started rough ...real rough...check engine light started blinking...then went solid for awhile ..then started blinking again...Got up to highway miles ~65 miles/hr ran fine..I drove it home and parked it..
Drove it this morning..solid check engine light and autozone provided me these codes. PO206, PO432, and PO306.
Everything from fuel injecter to catalytic convert to misfire in cylinder 6..

Where do I start?
any suggestions appreiciated.

Thanks

captainwoot

I woulod clear them and see what re occurs, the fuel injector could cause this misfire code and dump fuel into the exhaust and cause the catalyst code......tune-up and everything in good shape?

Jeepney

What would you suggest for a tune-up? Of course spark plugs...but what else?...i have no distributor or spark plug wires. Should I replace the spark plug distributor rail as well....sorry I know that's not the correct name for it.you know what I mean though.

01cherokeexj

The spark plug rail would be the coil pack, I had somewhat of the same problem with my '01 and it turned out to just be the spark plugs setting off the random cylinder misfire code.

EastBeast

You can check your plugs, injectors, and rail for free and either find a problem or rule them out. If you don't have one, i would buy a decent meter before throwing a lot of money at parts. Your exhaust may smell like rotten eggs kinda if the cat is bad.

Gorillaxj

I would pull a plug and see how it looks or just replace them if you don't know the condition. while the plug is out a compression test would be a great thing to do to make sure the engine is good. don't bother with the coil rail yet. not very likely to be the problem with the codes it has. tune-up is just plugs for this year. from the listed codes i would start with swaping the #6 injector with cylender #1, its most likely an injector. this is a good way to test the injector or eliminate it with limited tools and diag equipment is to swap it to another cylinder and see what code returns. if the misfire moves to the cylinder you switched it to then its the injector. if not then the problem is still back at cyl #6...


with an injector code i would guess the injector is bad and either not opening enough and the computer has detected high resistance or stuck open and dumping fuel. with the newer jeeps that have a return-less fuel system it is common for contaminants to get stuck in the fuel rail and clog injectors or have them jam the needle causing them to leak extra fuel. good time to clean the rail if you replace the injector. (also a good time to do an injector swap if you are replacing 1 already)

the cat code is most likely set from the misfire and improper fuel trims from a miss while your drove it with the light flashing. (flashing light means your damaging the catalyst) ignore the cat code until the others are fixed, if it returns you may have done enough damage to it while driving with it blinking to need a new one.

code info from alldata....
p0206- INJECTOR # 6 CONTROL CIRCUIT
POSSIBLE CAUSES
Wiring harness inspection
ASD relay output circuit
Fuel injector
Fuel injector driver circuit open
Fuel injector driver circuit shorted to ground
Powertrain control module
p0306- CYLINDER # 6 MISFIRE
POSSIBLE CAUSES
Engine mechanical problem
Erratic cam/crank sensor signals
Fuel system problem
Misfire conditions no longer exist
Other possible causes for misfire
Secondary ignition or mechanical problem

Jeepney

Okay...thanks for the advice. Luckily I have an extra vehicle. Ill probably get to it this weekend

tjwalker

The P0206 is CAUSING the P0306, and the P0432. A problem with the injector circuit for that cylinder is leading to the misfires, and the misfires are screwing with the catalytic converter efficiency.

I would definitely start by chasing the P0206.

Trust your OBD diagnostic system on this one. You have a fuel injector or fuel injector circuit issue with cylinder #6.

Start by swapping the injector from that cylinder with another cylinder. If the misfire follows with the swap, you know what injector to replace.

Also be sure that the injector connector and wiring are all good.

And don't drive it until you resolve. A flashing check engine light indicates a serious misfire, which if not resolved quickly, will destroy your catalytic converter.

Jeepney

If it proves to be an injector. Would it be wise to replace the other 5?..thinking if one goes bad the others are sure to follow?
Thanks again for the replies

Gorillaxj

Not really, I would replace just the one, the others should be ok. but it's a good time for an injector upgrade if thats something you would be interested in.

razor02097

not necessarily. Unless you are planning on upgrading to a different injector.