Commander 3.0l crd engine problem "PLEASE HELP"

[gleeson235]

I own a 2007 commander 3.0l CRD with 140,000 km's.
About 3 months ago, it started throwing P2138 & P2121 fault codes, throttle position sensor. The engine light & the red lightning bolt light came on & it went into limp mode. Turn the engine off, remove key, inset key, restart engine, off you go, sometimes for days, sometimes for seconds. As it is out of warranty, i took it to a auto electricians with Jeep experience. The throttle sensor was replaced but the problem continued. He was sent test procedures to test the code but everything tested OK. Tests were run again, still ok. He was told that if the tests are all good, it’s the CPU. He was not convinced & neither am I.

So i hit the net for common problems.
Swirl motor??? Remover the turbo intake tube & watched the swirl motor moving freely when engine was reved.
Cat clogged??? Removed cats & all look ok. (NOT EASY)
Intercooler blocked??? Have not removed yet but is next on my list.

When i removed the inlet tube & revved the engine to see if the swirl motor operated, i noticed that when it was revving, it was sucking like crazy, but when you backed off, it actually blew air back out the turbo inlet with a big hissing sound. Is this normal????
I know it a Variable-geometry turbocharger but i have no idea of characteristics.

If you push the accelerator down slowly, it picks up revs & will drive but if you push it down quickly, it lightning bolts & goes into limp. Even if it drives, it surges terribly.
Sorry for being so long winded but i am trying to include all info available.
If anyone can help in any way, it would be appreciated, i am at witts end.

[08crd]

Originally Posted by gleeson235

I own a 2007 commander 3.0l CRD with 140,000 km's.
About 3 months ago, it started throwing P2138 & P2121 fault codes, throttle position sensor. The engine light & the red lightning bolt light came on & it went into limp mode. Turn the engine off, remove key, inset key, restart engine, off you go, sometimes for days, sometimes for seconds. As it is out of warranty, i took it to a auto electricians with Jeep experience. The throttle sensor was replaced but the problem continued. He was sent test procedures to test the code but everything tested OK. Tests were run again, still ok. He was told that if the tests are all good, it’s the CPU. He was not convinced & neither am I.

So i hit the net for common problems.
Swirl motor??? Remover the turbo intake tube & watched the swirl motor moving freely when engine was reved.
Cat clogged??? Removed cats & all look ok. (NOT EASY)
Intercooler blocked??? Have not removed yet but is next on my list.

When i removed the inlet tube & revved the engine to see if the swirl motor operated, i noticed that when it was revving, it was sucking like crazy, but when you backed off, it actually blew air back out the turbo inlet with a big hissing sound. Is this normal????
I know it a Variable-geometry turbocharger but i have no idea of characteristics.

If you push the accelerator down slowly, it picks up revs & will drive but if you push it down quickly, it lightning bolts & goes into limp. Even if it drives, it surges terribly.
Sorry for being so long winded but i am trying to include all info available.
If anyone can help in any way, it would be appreciated, i am at witts end.

So you have replaced the potentiometer on the accelerator pedal?
I am no expert on engine management systems and only a bit of a bush mechanic.
However applying logics to the symptoms, the e.c.u has to get signals from several inputs to confirm what is happening. Therefore if you put your foot down on the accelerator the potentiometer changes the voltage to the relevant input. Then the e.c.u will look for an increase in revs from the crankshaft position sensor and a corresponding increase in air flow at the m.a.f sensor. The e.c.u will then increase fueling to match the inputs, it then will trim the fuel with the o2 sensor in the exhaust.
This all happens in milliseconds, if one of the above inputs doesn't correspond with another a fault code is thrown.
It is interesting that you say if you rev it slowly everything is o.k but if you stab the accelerator it goes to limp mode also that the engine surges on a steady throttle.
If the accelerator pedal positioner has been replaced my first guess would be crank shaft position sensor, second guess would be maf sensor on your air inlet tube just after the airbox. I doubt it will be the e.c.u but you never know. Work from the cheapest fix upwards and see if you can just swap the maf sensor with another jeep 3.0L they are easy to get to. It may also be worth just unpluging the throttle positioner connectors and replugging them back in all the way to the ecu input, just might be a dirty or bad connection
Best of luck.

[Fud]

I've had to replace my Crank Angle sensor or Crank Position Sensor at 120000, might be worth a shot if you haven't done it yet.

[gleeson235]

Thanks for you input guys. I haven't spent allot of time looking at the other sensors as the codes point at the throttle but looking at other threads there not always right. I will be checking them before i go spending any money on swirl motor or such. I'm sure it can't be too much as it starts & idles fine with no noise. I also spoke to a turbo specialist & he said that it not uncommon for the Variable geometry turbocharger to do that as that don't have a waste gate or dump valve.
By the way Fud, what were the symptoms of you crank angle sensor failure?

[vk2jdh]

I would take it to a jeep dealer and have them run the swirl motor diagnostics tests with their starscan tool. Most non jeep places won't have the scan tool to diagnose .

[Fud]

It was a bit different to yours experience, the car would drive perfectly for 10-15 minutes then splutter and stop, the engine light & the red lightning bolt light came on and the wouldn't restart for an hour or so just crank over continually. Didn't have my scan gauge then so I can't tell you the codes. Good luck.

[multihull]

Here a place to get replacements fast and cheap ex the USA.

I have already bought a few parts from Euro Parts - San Diego. Glow plugs, Serpentine belt, 10 x oil filters and they have all been a perfect fit and high quality. Delivery time is about 5 days. The Late model Merc Sprinter van has the same engine as the Commander V6 Merc diesel and as you know commercial vans do heaps of miles and need cheap and reliable parts. This is a great benefit for us Commander owners.

Here's the link: http://store.europarts-sd.com/engine..._4.aspx?page=2