Jaguar XF P0506 - Rough Idle and Stalling at Stops

Question

My 2012 XF is acting up whenever I come to a red light, with the RPMs dipping down to 500 and the whole car vibrating. It feels like it wants to stall out, and twice now the engine has died completely while sitting in traffic. The CEL is on with a permanent P0506 code and I am worried about it being a vacuum leak.

turbo_tony · Accepted Answer

The issue was a combination of a heavily carbon-fouled throttle body and a cracked plastic PCV hose on the passenger side. I cleaned the throttle bore with a lint-free cloth and throttle plate cleaner, then replaced the breather hose (Part #C2D20103). After performing the 'Throttle Position Sensor Adaptation' reset using an SDD tool, the idle stabilized perfectly at 650 RPM and the P0506 has not returned.

wrenchqueen · Answer

You should smoke test the intake system. Those AJ133 engines are notorious for the PCV diaphragms tearing in the valve covers, which creates a vacuum leak that the computer tries to compensate for by dropping the idle.

Ashley Park · Answer

Check the throttle body for carbon buildup around the butterfly valve. Even a small amount of gunk can prevent the blade from finding its home position, which causes the ECM to struggle with idle air management.

Tom Patel · Answer

Look at your MAF sensor data on a live scanner. If the grams per second are skewed, the ECU won't command the correct idle air volume. Clean the sensors with dedicated MAF cleaner before replacing anything.

Jaguar XF P0506 - Rough Idle and Stalling at Stops

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