Range Rover Evap System Undertanding and issues

Andrew Technician Grand Rapids, Michigan Posted   Latest   Edited  
Question
Driveability
2013 Land Rover Range Rover Evoque Prestige 2.0L 6-spd (Aisin AW F21)
P144C

This Rover came in with Evap system fault P144C (Evaporative Emission System Purge Flow Performance During Boost) from a Car dealer that we service a lot of their vehicles. I cleared the faults initially and test drove. I found that the fault would come back after just a short drive maybe a couple minutes. I found a TSB related to the concern about PCM Programming for correcting the issues. We have the Drive Pro Scan tool and we were able to check to see if the Software was current in the PCM. Apparently it was all up to date. I checked for any leaks in the Evap system and found that with purge valve disconnected electrically I was seeing vacuum still being pulled on the Tank side of the EVAP Line. Ok, So I thought i was getting somewhere. I replaced the Evap purge which includes a whole lot of lines for this Evap system. I test drove the vehicle to verify the faults would no longer return. I was wrong faults returned after a short test drive again. I wanted to verify the function of the Evap purge by looking at the scan tool and the Scope to make sure things matched up. I could watch the Evap purge activate on the Scan tool as well as the scope. I am not sure exactly how I could check flow through the evap system by watching values of my lambda or Oxygen sensors or some other sensor values. Any ideas? I have verifed the DMTL is able seal off the system when I activate it manually. The Scan tool will not completed the EVAP test either. Not because of any condition of the car I just think the test is not supported properly. Any Ideas on this one? Thanks 

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Vincent Diagnostician
Dallas, Texas
Vincent Default
 

No other codes setting for secondary purge connection? If it’s only P144C I would look in the direction of the (over)boost solenoid for the turbo and in very rare cases an obstruction in the charcoal canister. If you have any secondary purge flow codes the PCV diaphragm (under the intake) may be at fault.

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Andrew Technician
Grand Rapids, Michigan
Andrew Default
 

Thanks Vincent for the insight. I do have only that one code. I did notice one thing after the Rover idled for a while that the vehicle did have some oil smoke out the Tailpipe. I pull the dipstick and check PCV vacuum and did not notice anything odd but the smoking thing kinda stuck in the back of my head. Also I did smoke test the Evap system and with the DMTL open and smoke rolled through the…

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Vincent Diagnostician
Dallas, Texas
Vincent Default
 

The only possible cause as listed in the OEM information is ‘secondary purge valve pipe disconnected’. If the DMTL active stall test passes and purge/secondary purge connection has been renewed already it will be your PCV. The secondary purge connection is the connection on the elbow under the throttle body. It this is air tight and has no leak PCV replacement will be required. I wish I could…

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Andrew Diagnostician
Grand Rapids, Michigan
Andrew Default
   

Do you know if the software version could have some update within it and still have the same software part number? Or do they always add a new part number to a revision.

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Andrew Technician
Grand Rapids, Michigan
Andrew Resolution
 

Hey Just wanted to update the Post and close this one up. After many tests on the Purge system and it operation I found that everything in the Evap system was functional. I thought the only likely remaining possibility would be a software internal issue or a PCM logic issues. We attempted to have the PCM programmed remotely and was told it was updated with the most current software. I was not…

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