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Join Date: Apr 2011
Location: United Kingdom
In the parameters section of FES, tick both the Exhaust Phase Variator Desired Value and Exhaust Phase Variator Actual Value boxes. The software will now display the value the ECU expects to see and the actual value determined by the sensor on the exhaust camshaft. It might also be helpful to view the parameters as a graph.
The likely reason for the code is that the values don't match (i.e. the cam isn't where it should be relative to the crank) - either at some load/rpm point or across all load/rpm combinations. There will always be small differences and the actual value will lag slightly behind the desired as the hydraulics catch-up. What we're looking for is a difference of several degrees in steady-state operation.
Diagnosing what's actually wrong mightn't be simple as there are a number of possibilites that could cause the problem. E.g. basic cam timing (pulley a tooth out) failed phaser unit, failed control valve for phaser unit or failed cam sensor. Each of these would show up differently in FES and all but the basic cam timing could also be intermittent.
1) Cam sensor failure - no data in actual value or unfeasible values
2) Basic cam timing - difference between desired/actual values when the phaser can't move the cam far enough to compensate for the pulley being misaligned. Also possible constant difference between desired/actual values
3) Faulty phaser/ control valve - variable differences between desired/actual.
Not sure if the control valve would throw a separate code if faulty - would depend if it's a hydraulic or electrical issue.
Ian from Manchester, UK
(Certifiable Car Nut)!
Current Alfa: 159 Sportwagon 2.2 JTS
Previous Alfas: 156 2.5, 164 3.0, 75 3.0
Other Current Cars: Porsche 997S Gen-2 PDK, BMW Z4 sDrive 23i
Last edited by Ian_UK1; 09-12-11 at 12:16.