Two weekends ago I picked up a 2003 Disco S with 128k on it. The previous owner said that it wouldn't run when warm in traffic, but would go fine while driving. I purchased it and got stuck in Atlanta traffic instantly. making it about 10 miles before it died at a light. Luckily I had a friend in the area that let me tow it to his place. Once there i pulled the codes and had the following: P0101, P0505, P0335, P0336, P1884, P1668. I grabbed a new CPS and installed it. Fired it up and it ran for about ten minutes before sputtering hard. I shut it down, rented a trailer, and brought it home.

Once I got it home, I pulled the Iacv and cleaned it, tested it for resistance(10.9 &12.2 ohms), and re-installed. I also swapped the MAF, and replaced the fuel pump relay. Then cleared codes and started it up, let it warm for a few minutes and dove it around my neighborhood. After pulling back into the driveway it began to stutter in park. Pulled the codes again and P0101 and P0505. I tested battery voltage at 12.7v not running. Checked voltage at the Maf plug with the key on.
T1=4.98v
T2=12.43v
T3=.01v
T4=5.00v

Then tested the voltage at the Iacv with key on.
Blue= 2.79v
Brown/red=12.39v
Green/red=2.78v

Next I pulled the the TPS and checked resistance.
Points 1 &3 on the TPS= 1.1 ohms to 3.3 ohms with smooth transition as turned
points 1&2 on the TPS= 2.4 ohms with no change on rotation.

After cooling, I started it back up to put it in the garage. Pulled the Maf plug and the idle got worse. After reconnecting it i checked voltage at the battery with the engine running and got 14.25v at idle.

After being out of town for a few days, I am back on it today. I pulled it out and let it warm up in the driveway. It idles at 700-750 until it begins to stutter. Shut it down again and check the codes P0101, P0505, P0335, P1884. Having replaced the CPS a week ago, I wasn't expecting to see its code again so soon. I waited about 45 minutes and started it again to get a video. If anyone has any ideas of where to go from here I'm all ears. I just don't want to go down the rabbit hole of throwing parts at it, and would prefer to keep it out of the shop unless completely necessary. Thanks!

https://youtu.be/Xlv-To5DbSQ

 

I should also note, while having the Iacv and Maf out, I checked the throttle body. It was clean. Also the air filter is clean.

The previous owner replaced the plugs and wires, along with the fuel pump before i got it as well.

 

The RAVE does say "Whenever a new crankshaft position sensor is fitted or the flywheel is removed, the adaptive values will have to be
reset, using TestBook."

That said the common experience reported on this forum, and my experience, is that no adaptive values reset is required. Maybe yours is a special case because of how long the truck was driven with a faulty CKP sensor. Just brainstorming.

 

Check RAVE Manual P18-2-36 for trouble shooting and symptoms.

 

mln01- Thanks for the heads up. Im hoping that I don't have to have the adaptive values reset. With the other codes, I am going to get it as sorted as my skill set will allow. Then if need be I will take it in and have them reset.

LR03NJ- I am reading it now. Am i correct in understanding that the idle would default to 1200 RPMs if the Iacv fails? I was suspicious the rotary valve may be seized. Is there a test for this? From what i had read prior to cleaning it, it is not supposed to be forced to move.

 

You can check this article if problem persist. You might find a similar or cheaper replacement.
Idle Control Valve - idle problems; get to know it - Land Rover Forums : Land Rover and Range Rover Forum

 

I think I may have found an issue while checking the ECM connector 0636. When locating the red/green wire( pin 43) to test for the actuator close voltage, I got a sound from the engine bay. By moving that wire I can replicate it. Unfortunately I don't have someone to move it while I source the sound. I'm going to test it tomorrow when I have a second set of hands present and I will report back.

 

Update... with some good news. I pulled the rig out of the garage this morning and while it was warming up, I fiddled with the red/green wire. And the truck began to stumble and then came back. So I shut it down, wedged the wire in, cleared the codes, started it up and grabbed a cup of coffee. Thirty minutes later it was still running. Then I hopped in and went for a ride around the neighborhood. It kept running, so I got bold and started looking for stop signs. After another hour it was still running and I had hit every stop sign nearby at least twice.

The engine speed is floating some. At idle and when selecting gears. the p0101 and p0505 codes came back. At this point I am going to re-pin that wire in the connector and get an Iacv on the way. I will report back with any changes. Now I'm gonna do some more "Testing".😎

 

Wow! Great troubleshooting. You got 128k miles on that. Since you pinned the problem, why not got a replacement part and worry about the next issue. Electrical contacts are troublesome. Run that for another great 128k.

 

Thanks! Your post on the Rave is what led me to it, so thank you for that!
As far as replacement, if the plug holds the new pin tight, then it would be far less work/cost than replacing the connector or the harness. If it seats loosely then I will explore those options.
🍺Here is to hoping, with a little patience, funds, and elbow grease, I can get another 128k out of it.