P3435: Cylinder 5 Deactivation/Intake Valve Control Circuit Low

What does P3435 mean?

P3435 flags a short to ground on the control line of the cylinder 5 deactivation valve. GM documents it codewise twice: in the 2019 tables for the L84 V8, with under 0.5 ohm to ground in the driver-off state, 20 of 25 samples at 250 ms and Type B, and in an engineering bulletin for 3.6 L V6 engines (LGX, LGZ) where P3435 appears along with P3433 and P3409 when oil leaks from the rocker arm control valve. Oil that wicks into the connector can create exactly such a leakage path. P3433 is the open circuit, P3436 the short to power, P3434 a mechanical failure. In daily driving the engine simply stays on all cylinders.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine lamp on
• Oil wetness at the valve cover around the control valve (V6)
• No fuel-saving cylinder deactivation

Common causes

• High Oil in the cylinder 5 valve connector creating a leakage path (GM 3.6 L V6)
• Medium Control wire shorted to ground
• Medium Shorted cylinder 5 solenoid
• Low Engine control module driver fault

Likelihood is a general estimate across vehicles; your make and model may differ.