Randomly enters into limp (?) mode- rough idle
 

My X5 has been running pretty smoothly the last 6 months. I don't drive from the often (once a week ~10kms) and have done a few long trips (300 kms).

However this week- it seems to randomly to into "limp" mode. Idling becomes rough, and accelerating is patchy.

It normally only happens at ignition, and often turning it off and on gets rid of the problem (car runs fine, no errors get reported/ODBII is clear).

However, today it happened while driving.

What could be triggering this limp mode?

It possible I have a temperamental o2 sensor triggering it?

Work I did with in 12 months- CCV Replaced, alternator, disa valve.

ODBII tells me:
P0115- power train O2 Heat sensor
P1349 P1351 P1352- tap for multiple descriptions
P0300- random misfire detection.

Check your codes again and I would bet that your misfiring cylinders change after clearing... i.e. 1,3,4,7 to 1,3,5,8 or whatever.

I'm not sure what causes it but I've had it happen also, but I think the cylinder changes is caused by the temperature O2 sensor error. As to if something else causes the O2 temp sensor fault I don't know but my mechanic will come by the compound later in the week and I'll ask him then, but if you find out I'd be very interested in the cause.

:popcorn:

Randomly enters into limp (?) mode- rough idle
 

The 02 heat won't cause limp mode my car has has that problem for 7 months.

Go-to on random limp mode is bad plug. Did you replace the plugs?

I had three of those events over about a year. "Misfire with fuel shut off"

Wife's car had it bad: couldn't drive more than about 20 miles at the end without misfire / limp.

Changed her horrible looking plugs and back to normal. I then realized probably why I would get the same exact error occasionally so I changed my plugs as well.

(No misfire since and bonus better mpg)

I had a similar issue with occasional rough idle and misfires. Turned out to be a torn intake boot. I got the yellow cog warning light and it downshifted harder when it occurred.

Been wondering, mcfee03, did you ever find that missing DISA pin...? :confused:

I think the answer was established: no I'm betting it's on the foam pad under the engine.

No, I didn't replace any of the plugs. Would you recommend replacing all at once? Is there a way to examine them to see their 'condition'?

Any particular brand/model you'd recommend?

Na, never found it. Spent like 4 months looking for it on/off (and not driving) including a wire camera, taking the intake out, removing all the pistons. FWIW did take it to a local mechanic too, who checked over my work and said it was running great

Some pretty huge steps given I'd never done any mechanical work before!

Randomly enters into limp (?) mode- rough idle
 

NGK Platinum. OE

Code will usually repeat on a cylinder. Pull that plug and one without a code and compare.

When I did wife's car, the trouble cylinder plug was wet and gross.

Same happened to my friend and after several trips to the dealer it turned out to be a bad battery....worth checking it if you haven't already.

Sent from my SM-G900F using Tapatalk

P1349 BMW - Misfire Cylinder 4 With Fuel Cut-Off

P1351 BMW - Misfire Cylinder 5 With Fuel Cut-Off

P1352 BMW - Misfire During Start Cylinder 6

Base on what you wrote and the codes you posted, you have a misfire(s) with injector cutoff. Restarting the engine just reset the misfire counter back to 0 and the injector(s) that was turned off by the computer is now back on. Could be a bad plug(s) or a bad coil(s). It would be cheaper right now to just replace the plugs if they haven't been done recently.

Other things to look at because you have 3 cylinders that are misfiring is for an Intake vacuum leak or a Faulty Camshaft Position Sensor.

A misfire in today modern computer controlled engine is not the same as a misfire in the old carburetted engine of days gone by. A misfire in today engine means the computer has detected that one cylinder or multiple cylinders are not providing as much power when it fires as compared with the other cylinders. A lean condition could account for a misfire as well as an unhealthy engine with low compression in one or more cylinders. So don't go by the old way of thinking that a misfire is only related to spark plug and coil.

That's very accurate. The crankshaft position sensor measures how far the engine turn each time a cylinder fires and if it's delayed by milliseconds it knows that that cylinder didn't do its job correctly

Limp mode is beginning to happen more often :(

I don't have my odb with me, so no codes.

Turning the engine off for about 1 seconds gets rid of it.

Also, it seems to be (maybe) chewing through a lot of fuel.

Just so I understand- my first recommended step it to replace the plugs? My local store sells Bosche- is it worth delaying to get NGK?

Is there anything to look for on the plugs or coils- I remember once hearing about a mayonnaise like substance being an indicator of something?

Then coils? Then the crankshaft position sensor?

It sounds exactly like wife's car and was just plugs.

I cleaned and gapped her plugs and it ran much better until I got plugs. I think I may have used Bosch Platinum 4 in her car.




Sent from my iPhone using Tapatalk Pro

Just replaced all the spark plugs (with Bosche)- and sadly the car just entered into limp mode after about 10 minutes of drivung :(

Odb codes are now:
C3113- Chassis (haven't seen this before, only popped up once...)
P0001- power train
P0155- o2 head sensor
P0171- too lean (bank 1)
p1349- misfire cylinder 4
P1351- misfire cylinder 5
P1353- misfire cyclinder 6
P0300 random misfire
p1346 misfire during start cylinder 6

Is torque/tension on spark plugs/coils important? I definetly had difficulty getting the back plugs in tight.

What is next to do?

Did you look for a vacuum leak? You have a P0171 lean code which will be a vacuum leak. Check the rubber boot from the MAF to the throttle body, in particular, the rubber extension to the Idle Air Control valve. That is a known leaker.

http://i917.photobucket.com/albums/a...werboot002.jpg

I had that exact leak. I didn't know about it until my disa failed. Terrible idle. I looked for a leak and my finger went right into the hose


Sent from my iPhone using Tapatalk Pro

If you have a scanner that can show real-time activities, you can look at the long term and short term fuel trim. If you have positive fuel trim that means the computer is adding fuel to the mixture. This could be because the engine sees a Lean condition so it is trying to compensate for a lean condition. I would find out what the problem is before driving the X or else all that excessive fuel is going to ruin the catalytic converter, assuming in your neck of the wood you have catalytic converters on your cars.