P1349 – Variable Valve Timing System Malfunction Bank 1 (LEXUS, TOYOTA)

By Reinier (Contact Me)
Last Updated 2019-09-19
Automobile Repair Shop Owner

Manufacturer Specific Definitions for P1349

Table of Contents

1. What Does Code P1349 Mean?
2. Where is the P1349 sensor located?
3. What are the common causes of code P1349?
4. What are the symptoms of code P1349?
5. Get Help with P1349

What Does Code P1349 Mean?

OBD II fault code P1349 is a manufacturer specific code that is defined by car makers Toyota and Lexus as “Variable Valve Timing System Malfunction Bank 1”, and is set on these applications when the PCM (Powertrain Control Module) detects a failure, defect, or malfunction in the VVT (Variable Valve Timing system on Bank 1. Note that Bank 1 refers to the bank of cylinders that contains cylinder #1 on V-type engines.

Although there major design differences between variable valve timing systems in use by different vehicle manufacturers, the function of these systems are largely the same, regardless of the application. In fact, all variable valve timing systems have two things in common, these being that a), retarding or advancing the camshafts relative to a fixed base setting can change the engines’ volumetric efficiency to produce more power at some engine speeds, and b), that changing the volumetric efficiency of an engine lets an engine develop more power, while reducing emissions and using less fuel, at the same time.

As a practical matter, the variable valve timing systems on Toyota and Lexus applications uses pressurized engine oil to activate an actuator that is attached to the intake camshaft. When the VVT system is not in operation, the valve timing operates at its base settings. However, when the system is activated, the PCM commands a control solenoid to open, which causes a metered amount of pressurized engine oil to act on the actuator. This in turn, causes the camshaft to rotate either with, or against its normal direction of rotation, which has the effect of either advancing, or retarding the phasing of the camshaft relative to a fixed, base setting.

Which direction the phasing is changed to depends on both the current operating conditions, and control inputs such as large throttle inputs. Nonetheless, when the system is activated, the practical effect is that the altered camshaft phasing causes the intake valves to open sooner, or to stay open longer, both of which conditions improve the airflow through the intake manifold and runners. This in turn, improves the mixing of the air and fuel, which in its turn, improves combustion and reduces emissions.

When the VVT system is deactivated, the pressurized engine oil is returned to the main circulation system via the oil control solenoid, and the actuator returns the intake camshaft to its base setting. It should be noted though that on some applications, the phasing of both the intake and exhaust camshafts can be altered both with respect to each other, and to fixed, base settings to produce a larger range of possible phase changes.

Regardless of the system though, when a defect, failure, or malfunction occurs anywhere in the VVT system, the PCM will recognize that it cannot control the VVT system effectively, and it will set code P1349 and illuminate a warning light as a result.

Where is the P1349 sensor located?

The image above shows the location (circled) of a VVT oil control solenoid on a Lexus application. Note that since the actual appearance and location of VVT oil control solenoids vary greatly between Toyota applications, reliable service information must be consulted to locate and identify VVT oil control solenoids accurately. Failure to do this could result in misdiagnoses, wasted time, and the unnecessary replacement of parts and/or components.

What are the common causes of code P1349?

The causes of code P1349 on Toyota and Lexus applications are many and varied, but could include one or more of the following-

• Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors in the VVT systems’ various wiring harnesses
• Damaged or defective VVT oil control solenoid(s)
• Damaged or defective VVT actuator(s)
• Use of substandard aftermarket VVT oil control solenoid(s)
• Low engine oil level
• Low, or insufficient oil pressure
• Use of unsuitable, or incorrect engine oil
• Dirty, degraded, or contaminated engine oil
• Failed or failing PCM, but note that since this is a rare event, the fault must be sought elsewhere before any control module is replaced

What are the symptoms of code P1349?

The most common symptoms of code P1349 on Toyota and Lexus applications largely depend on the nature of the failure or defect, but could include one or more of the following-

• Stored trouble code and illuminated warning light
• In some cases, multiple additional trouble codes could be present along with P1349- most notably, codes relating to misfires
• Engine may be difficult to start, or extended cranking times may be required before the engine starts
• Idling speed may be erratic, or fluctuate wildly
• Idling may be rough, or the engine may not idle at all
• Various degrees of power loss may be present at some, or at all engine speeds
• Fuel economy may be extremely poor
• Engine may stall at low engine speeds, or the engine may stall and/or hesitate unexpectedly under acceleration
• Catalytic converter damage may occur if the fault is allowed to persist for extended periods
• Engine may back fire through either the exhaust or intake manifolds upon deceleration

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