General Automotive

Chevy Cruze, Sonic, Trax, & Buick Encore 1.4L Turbo PCV Valve Issues

An overview of PCV issues affecting the 1.4L Turbo LUV/LUJ engine in your Cruze, Sonic, or Trax, or Encore. This contains documentation, links to resources, and steps for diagnosis so you can get back on the road successfully.

Affected Models

2011-2015 & 2016 Limited Chevrolet Cruze 1.4L Turbo
2012-2018 Chevrolet Sonic 1.4L Turbo
2013-2018 Chevrolet Trax 1.4L Turbo
2013-2018 Buick Encore 1.4L Turbo (Excludes Sport Touring)

Overview

Turbo engines require two PCV check valves. To evacuate pressure from the crankcase, a normal engine has a valve that opens to allow pressure into the intake duct or intake manifold. With a turbo engine, the intake and intake manifold are under pressure when building power, which requires an alternate path for PCV gas to escape. As a result, an additional check valve is placed to allow gas to evacuate upstream of the turbo.

In the 1.4L Turbo, these check valves are at the turbo inlet and inside the intake manifold. If you’re reading this, you may think that there is a check valve in the valve/camshaft cover, but that is simply a PCV pressure regulator diaphragm and not a check valve. The check valve is a little round disc with a nipple inside the intake manifold.

The below image explains the PCV path for this engine.

Cruze PCV System
Cruze PCV System

A full, detailed explanation of this PCV system can be found at the following link: 1.4L Turbo LUV/LUJ PCV System Explained.

Common Issues

You’ve probably found this article because you have issues with your vehicle. The two most common issues that affect this engine’s PCV system are as follows:

  1. The valve/camshaft cover’s pressure regulator diaphragm ruptures. This is located directly under the disc that you can see if you pull the coil pack/engine cover off. When this goes out, it will cause a hissing sound, and may cause oil to be splattered about the engine bay. This is often accompanied by rough idle. If you place your finger over the vent opening, the idle will smooth out. This usually triggers a check engine light.
  2. The intake manifold check valve disappears, causing elevated oil consumption and can potentially trigger a check engine light. This can go unknown to the owner for quite some time, but the effects, when accompanied by elevated oil consumption, can be disastrous.
  3. The corrugated hose from the intake manifold to the turbo cracks and creates a vacuum leak, or the check valve at the turbo inlet gets stuck closed.

Both of the first two components that fail are made of rubber that eventually becomes brittle and breaks. There is no preventive maintenance that can prevent this failure from occurring.

A brief overview of the issues and how to check if you have these symptoms is described in the following link:  1.4L Turbo LUV/LUJ PCV Issues.

Associated DTCs (Service Codes)

If you have a check engine light and get the codes scanned, the following service codes may indicate a PCV-related issue:

P0171
P0106
P1101
P0507
P0299
P2096

Available Solutions

If the PCV pressure regulator diaphragm on the Valve/Camshaft Cover has failed, your only recourse is to replace it.

Part Required: GM Part # 55573746

1.4L LUV/LUJ Valve/Camshaft Cover Replacement Tutorial

If the Intake Manifold Check Valve has failed, you have two options.

  1. You can replace the intake manifold with a new OEM one, at a cost of $250-$350 depending on where you purchase the intake manifold.
  2. You can replace the intake manifold with an aftermarket one. Dorman makes an intake manifold for ~$145-$180 shipped, depending on where you find it, but uses the same check valve design as the OEM manifold.
  3. You can retrofit an external check valve onto the existing intake manifold, at a cost of $85. The retrofit has the benefit of costing far less than a new manifold and lasting much longer, since it is a redesign of the flawed OEM system. In addition, it uses an external, serviceable check valve that is far more robust than needed for this application.  A new intake manifold will inevitably fail; the retrofit is much more robust. Use the links below to learn more about that kit: