P1059

What the Code Means

P1059 sets when the supply voltage to the Valvetronic actuator motor on bank 2 drops below 5 volts and stays there for at least 200 ms after the ignition is switched on. The DME monitors this continuously, because without correct power the motor can't set valve lift and the whole Valvetronic logic loses its reference.

The fault lies in the supply circuit, not the motor itself: a blown fuse, a faulty load reduction relay, or a break in the wiring harness.

Symptoms

• Check Engine light comes on;
• reduced engine power;
• rough idle;
• possible Valvetronic system failure.

Diagnosis and Repair

1. Check the Valvetronic (VVT) circuit fuse and replace it if blown.
2. Test the load reduction relay.
3. Inspect the wiring harness for a break in the motor supply and relay circuits.
4. Connect ISTA and monitor the actual Valvetronic motor supply voltage in real time.

A common diagnostic mistake is replacing the Valvetronic motor without checking the supply circuit: the code points to low voltage at the input, not a mechanical or electrical failure of the actuator itself.

Secondary Problems

If you ignore the fault, the Valvetronic system can fail completely, after which the engine drops into limp mode or stalls. Running for a long time on low voltage can damage the Valvetronic motor itself or the DME — at that point a “wiring and relay” fault turns into replacement of expensive components.