Ultragauge is reporting a pending P0101 fault, and the Lynx scanner says its a P0121 pending. Weird that they're different. Anywho, the code does not seem to turn into a fault when driving around town, but on the freeway and given enough time, I have seen the MIL lamp come on.

"P0121 Load Monitoring (Air Flow/to Throttle Angle) Fault. Value Not Plausible. Fault NOT Present and Intermittent." - Lynx

No noticeable drivability issues.

Transmission is also reporting an intermittent P1884 (38) Altitude Invalid, Fault Not Currently Present and Continuous. I can't find any diagnosis info on this one.

What I've done:

- Re-adjusted throttle and cruise control cables to correct gap
- Put in a new MAF (Bosch) and reset adaptive values
- Checked oil separator (super clean) and swapped it for the FRAM PCV nipple
- Checked air filter, replaced filter and MAF housing o-ring
- Checked throttle body, don't see any issues there
- Checked engine ground strap
- TPS sensor is reporting good data
- WD40 on the throttle body return spring

I remember getting this code fresh after my rebuild, and the issue was the gap on the throttle cable and/or return spring, the throttle would stick open and not return to closed, causing my fresh rebuild to spike to 4k rpm during the break-in period... whacking the tbody with a screwdriver would return the rpm to normal

 

Is it sticking anymore? I had several sticking TB’s a few months ago. I fixed them all by removing the TB, pinching the 3 screws that hold the throttle body plate in place, removing the TB plate from the TB, and cleaning it all the way around with a green scotchbrite pad (it looked clean, but apparently it wasn’t), after it was nice and smooth I re-installed it spread the tail on the 3 screws and those TB’s were as smooth as silk and no longer stuck or were sticky.

Might be worth a shot to do.

 

No, it hasn't stuck since the first break-in. Might be worth doing anyway though.

 

Quick and easy to do. I had those two throttle bodies looking brand new and they still stuck. Thats when I removed the throttle body plates and used the scotchbrite pad. Then they were both silky smooth afterwards with zero issues.

I haven't ever had to replace the TPS on a P38/D2, but that "could" be an issue as our P38/D2's aren't getting any younger. I probably ended up with close to 20 throttle bodies if not more that were all replaced under warranty due to that silly TBH. Before LR had the kits to repair just the TBH they were just replacing the entire unit. I personally don't use the TBH's as I find it a serious weak link in the cooling system so I removed all the INOP TBH's cleaned them up and have used them for spares for years.

 

Thanks.

Code appears to have morphed into P0441. Intermittent. I've had this code in the past, mostly pending, and I replaced the evap thingy and the SAI solenoid on the driver side intake a few months ago. Hasn't returned until now. Must be a small leak somewhere... how to find it is the question

 

Gas cap seat well? I've had P0441 due to a bad cap and the threads inside the filler neck causing a poor seal.

 

I chased this rabbit for a while.

I always recommend cleaning the gas cap and spout when P0441 shows up.

 

Best4x4, how to dismantle the throttle plate? Do I have to remove the TPS and the nut on the spring side?

I'm also considering removing the TBH, how did you do it? It seems the TBH also serve a purpose to help expel air in the system?

 

With the TB removed from the D2, you'll see 3 screws holding the throttle body plate onto the shaft itself. Take a small pair of needle nose and squeeze the threads of the screws closer (not all the way as you'll have to spread them back later), remove the 3 screws and the throttle body plate itself will come right off. You can then take it and use a scotchbrite pad on it to make it absolutely smooth. Installation is the opposite of the removal, just install the plate, tighten the 3 screws, spread the back of the bolts apart, and re-install the TB.

On the TBH I am a true believer in it being a Genuine POS and remove every single one of them! Several people have come onto these forums with claims of stuck throttle bodies due to the TBH being removed in cold weather and not a single one of them ever posted anything to prove it & then vanished into thin air as quickly as they'd posted and stirred up the pot....

It is a very poorly designed plate. with one screw being between 2 nipples. That does not allow for a very good seal and I've seen plenty of D2's and P38's die a very slow death as it bleeds out and the owner doesn't catch it and then once the coolant is low enough BOOM it's all over. The TBH plate used to be the #1 cause for Dexcool to get nasty as it was allowing air to seep into the system.

I just remove it, reroute the intake to the coolant reservoir and call it a day. I've driven my D2's in cold weather, and my best friend lived up in Wyoming and never had a single issue. Can a TB stick? sure... Is the TBH to blame? I doubt it... It's more like a dirty throttle body stuck in the cold vs the TBH caused it.

I had two LR's that had sticky TB's last winter. I had spares lying around so I swapped em out and sent them on there way. I inspected the TB's after they were gone and they were filthy!!!! I cleaned them up to where they looked 100% clean but they both stuck. I could rotate the TB Plate by hand and it would stick. I was going to toss them, but I wanted to see exactly what was going on so I tore them down, used scotchbrite pads on the TB plates and after that they were perfect and did not stick at all.

I honestly believe all the "sticking throttle body" stories we've heard about that have never had a single bit of info or follow ups are caused by dirty throttle bodies vs the TBH causing it. I mean our D2's aren't getting any younger and parts will eventually get corroded or stick.

If it was my D2 I'd ditch it and reroute the intake line to the reservoir, but the choice is yours. I have several friends in the PNW without their TBH and they've never had an issue.

 

"Take a small pair of needle nose and squeeze the threads of the screws closer"

I don't understand this part?

I have the 3 screws out, but the plate won't budge. I guess I just have to motivate it more?