P0243 help help 2.7 crd

[JeanLuke]

When you say "no resistance" do you mean zero ohms? If so, this is good. If you mean no connection (infinite resistance) then you have a broken connection or wire.

[ataiana]

So, I’m getting OL, so open loop it is. I should check all the wiring up to the ecu??? 🙃

[ataiana]

When you say "no resistance" do you mean zero ohms? If so, this is good. If you mean no connection (infinite resistance) then you have a broken connection or wire.

Update: after following some wires from the solenoid to the firewall nothing was broken. Later I decided to find out where the ground connection that feeds the solenoid (disconnected from the ecu) is located but no luck. In that process I found a loose hose with a plastic connector (it was the front differential vent tube) and connect it properly. After that no more open loop between the solenoid and ground (0.2oms). Tested out in road and P0243 came again after a hard acceleration (not all of them). Now I don't know if I have a bad ground that sometimes fails (only at more than 60mi/h and at 4000 revs) or it might be something else....
Someone knows which ground connection should I look for? Any other idea? Can a bad turbo trigger this error?
Thanks community

[JeanLuke]

That you have measured an open circuit, then had it work for a bit after you played under the bonnet is a strong indicator that you have a bad connection somewhere. The trick is where. It will be painful, but carefully trace it through.

It is for sure not a bad turbo. The error code you are getting is electrical, not mechanical. If it was the turbo you would be seeing P0235.

[ataiana]

Thanks JeanLuke. This post was super helpful and I saved lots of money not buying unnecessary parts. It’s really hard to test this bad ground with the pcm disconnected. Even harder is to reproduce the issue cause I need high engine temperature and high acceleration/final speed. Will be glad to test any suggestion and I’ll post findings to help in future diagnostics.

[ataiana]

A few things to check:

1. Fuse 16 in the power distribution centre is not blown. It provides power for the Auto Shut Down Relay (ASD Relay) which in turn provides power to the turbo solenoid.
   
2. Check there is 12V on pin 1 of the solenoid plug when the ignition is on. Pin 1 is on the right when looking at the plug with the connection tab at the top.
   
3. With the power off, unplug both the solenoid and the ECU. Then measure between pin 2 of the solenoid plug and pin 76 on the ECU C1 connector. The resistance should be below 10 ohms. C1 connector is the bigger one. Looking at the plug with the five big pins at the top, the right row is numbered from 63 at the bottom to 81 at the top. Count up from 63 to find pin 76.
   
4. With the power off, unplug both the solenoid and the ECU. Then measure the resistance from solenoid pin 2 to ground. It should be higher than 1000 ohms.

So, still can't solve this one. Step 4 (pin 2 to ground) still getting open loop. Where is this ground connection coming from? I've checked all visible ground connections and are okay. Is there any other ground connection that can be broken? Maybe down the chasis? Or I am missing the point of the failure?

[ataiana]

So, still can't solve this one. Step 4 (pin 2 to ground) still getting open loop. Where is this ground connection coming from? I've checked all visible ground connections and are okay. Is there any other ground connection that can be broken? Maybe down the chasis? Or I am missing the point of the failure?

Finally, it was non electric issue. Replaced the geometry and turbo. Solved