hi everybody,

i ve been reading this forum for a while to try figuring out the problem i have with my 2001 disco. (2001 V8, 116k)

i bought it from a friend a few month ago. a few weeks ago the service engine light went on and it showed p0327 (knock sensor bank 1 low input), and a large evap leak (forgot the code). i replaced the gas cap and everything worked fine till two weeks ago.

now it gave me p0154 - O2 sensor (malfunction bank 2 sensor 1) and p0327 knock sensor 1 (circuit low input bank 1 or sensor 1)

i had the O2 and the knock sensor changed yesterday. drove off the garage and the service engine light came on. they said they are going to look into it, but i am good to drive till tuesday.

this morning i drove it and suddenly the light starts blinking.
i ran the error codes and got the following errors:

P0154 O2 sensor no activity bank 2 sensor 1
P0155 O2 sensor circuit malfunction Bank2 Sensor 2
P0327 knock sensor 1 circuit low input bank 1 or sensor 1
P1300 DTC definition not found (no clue what that means)
P0308 cylinder 8 misfire
P0306 cylinder 6 misfire
P0304 cylinder 4 misfire
P0302 cylinder 2 misfire
P0300 Multiple cylinder misfire

it came up after acceleration uphill after a traffic light, then the light stopped blinking and engine seemed to be running smooth. (also, i didnt notice any loss in power)

i ve read in this forum that many disco II owners have problems of a similar kind that just eplacing the O2 sensors might not do the trick. also very strange that the misfires never happened before the O2 sensor got changed.

i hope somebody is able to help me out on what is the best solution to fix the problems and if anyone can recommend a place in nyc or surrounding area that might be familiar with that problem. just want to avoid fixing things that dont need to be fixed.

thank you

andreas

 

98% of all O2 codes are because of the need of a tune up, knock sensor codes can be caused by the same thing.
When the spark plugs and or spark plug wires are worn out you get weak spark.
Weak spark will cause to much unburnt fuel to be dumped down stream and the O2's will read "out of range" and throw a code.
Replace the O2's and the code comes back because the root cause was not fixed.
Weak spark can also cause pinging, also known as knocking, and because the knock sensor's cannot retard the ignition timing enough to make it stop knocking it throws a knock sensor code.
Using the wrong grade of gas will magnify the problem, premium fuel is required in these trucks, no if's and's or but's about it.
So, you need new spark plugs and spark plug wires, you must only use Magnecor, Kingsbourne or STI spark plug wires, anything else and you will be doing the job again in a month.

 

Sounds like a wiring harness or ECU issues to me, by the way you describe it and the multiple seemingly unrelated codes. What' it look like under the hood? It is a mess? Does the wiring harness look like it still has the plastic loom around it, or can you see a section that might be rubbing on something that has chaffed the insulation off one or more wires?

The flashing SES light is from the misfires. It is telling you that driving it that way will likely damage your cats.

Edit: What Spike said makes sense if you haven't been keeping up on maintenance. I assume the garage you took it to would know this, but maybe not. So my reply is assuming you have good plugs and wires and the truck is not due for maintenance you haven't done.

 

All of the misfire codes are on the same bank. The same bank as both oxygen sensor codes. I would check the wiring underhood. Make sure all of the connections are actually plugged in. Like Daryl said, the shop should have checked everything upstream of the O2 sensor before replacing it, but maybe they didn't.

The P1300 is "catalyst damaging misfire multiple cylinders"

 

i ve been only using premium fuel only and just checked the wiring. wiring looks good. plastic loom around is still there. also the spark plus wires look good. there is a little oil leak, but nothing major.

however the previous owner is a friend of mine and when i bought the car, he mentioned he never used premium fuel. he said he always did oil changes, but i am not sure if he did a real checkup...

i did service the car at a garage after i bought it just a few month ago and i have 1000 miles left until the next service is due.

as i mentioned,all wiring looks good; would that mean changing spark plugs and wiring would solve the entire problem?

i am very thankful for the help sincei am a rookie in dealing with car issues

 

You need to start with 4 new 02 sensors, plugs and wires.
If you want some help with this, send me your number and I'll call you this afternoon.

 

P.S.
how can i make sure that despite all wiring looking good, it is not the ECU?
by the way, is the ABS light, the TC light and another light coming on randomly also related to the ECU?

 

thank you very much, i ve never done such work on my own though (not sure if i can do it). i ll send u my number though

646 402 3397 available all day

 

Even if the spark plug wires LOOK good on the outside, you still have no idea what they are like on the inside (which is what really counts). You could use a multimeter and check resistance in each wire, but if they are original (grey color) they need to be replaced, unless you only have 40,000 miles on it.

The ABS, TC, and HDC lights coming on are probably NOT related to the ECU. Do a search on this forum for the "three amigos" or look at a few of the stickies at the top of this forum related to ABS.

 

i remember reading about the three amigos. was just making sure that they are not related here. as of now i d rather focus on getting the O2s replaced and replacing spark plugs and wires. (wire are blue, but they must have a few miles on them, since my friend cant remember changing them... he was the second owner and bought the car with 70k miles).
considering all this, they are probably due for a change...

btw anybody know of what the parts would cost in total (spark plugs, wires and O2 sensors - one has been replaced already). ballpark figure?!
any special brand in O2 sensors?

thanks again