A flashing glow plug light and a check engine light (MIL) can be concerning. This article details how to diagnose and fix a P0016 fault code – Camshaft Position (CMP) Sensor (G40) Bank 1/Engine Speed Sensor (G28) – Incorrect Correlation – on a 2015 VW Passat TDI SEL Premium. While the engine ran smoothly, the underlying issue required attention.
Initial Diagnosis and Timing Belt Replacement
Online research suggested a potential timing belt issue due to the age of the vehicle and potential storage time related to the diesel emissions issue. Despite having only 57,000 miles, a full timing belt kit was installed. The timing belt replacement process, using specialized tools, confirmed the engine timing was correct. However, the P0016 code persisted.
Sensor Replacement and Technical Bulletin 2040171
Next, the Camshaft Position Sensor (G40) was replaced, but the issue remained. Further research uncovered VW Technical Bulletin 2040171, which pointed to a potential problem with the camshaft adjuster control valve in the Gen III EA288 TDI engine. This valve consists of a solenoid and an adjuster valve itself. Replacing the solenoid proved unsuccessful.
Accessing the VW Repair Manual & Camshaft Adjuster Valve Replacement
To gain a deeper understanding of the repair process, a 24-hour access pass to the official VW repair manuals was purchased through erWin.vw.com. The manual detailed the procedure for replacing the camshaft adjuster valve, emphasizing the need to lock both the exhaust and intake camshafts in place at TDC (Top Dead Center).
The Repair Procedure
The procedure involved:
-
Accessing the Camshafts: Removing the upper timing belt cover, which required removing the fuel filter, rotating the coolant tank, and disconnecting various hoses and bolts.
-
Locking the Camshafts: Rotating the exhaust camshaft to TDC using an 18mm wrench and inserting the timing belt locking pin. The high-pressure fuel pump locking pin was then used to lock the intake camshaft by accessing a hole under the #1 cylinder injector harness connector on the valve cover.
-
Accessing the Adjuster Valve: Removing torx bolts to access the air filter area and gain access to the driver’s side of the intake camshaft.
-
Replacing the Valve: Removing the N205 solenoid to expose the adjuster valve. Using a 24mm socket, the old valve was removed, the new updated valve (Part Number: 03L 906 455 C) was installed, and torqued to 50 Nm.
Finally, all components were reassembled in reverse order.
Successful Resolution
Replacing the camshaft adjuster valve ultimately resolved the P0016 fault code and eliminated the flashing glow plug and MIL lights. This fix highlights the importance of accessing reliable technical information, such as official factory repair manuals, when diagnosing complex automotive issues, particularly on vehicles like the Vcds Passat Sel Premium.
