Question

2002 Infiniti I35 3.5L 6 Cyl with engine code P1800, what is this and how much to fix it?

Comments

It is reading P1800 and P0128 and it just came up today

Answer 1

You could start by checking the hoses connect to the VIAS control solenoid valve. If the hoses are OK, then you may have to replace the VIAS control solenoid valve. The valve is on top of the engine.

P1800 2002 INFINITI I35 - Variable Intake Air System Control Solenoid Valve Circuit
Read more: https://www.autocodes.com/p1800_2002_infiniti_i35.html

P0128 INFINITI - Thermostat Function
Read more: https://www.autocodes.com/p0128_infiniti.html