Nissan Altima P1801 VIAS Control Solenoid Valve

In the realm of OBD-II trouble codes for NISSAN vehicles, P1801 stands out as a significant identifier related to the Variable Intake Air System Control Solenoid Valve 2 (VIAS). This code may indicate potential issues with the VIAS control solenoid valve 2, impacting the performance of the power valve 2 control. We’ll delve into the description, possible causes, and recommended solutions for P1801.

P1801 – Code Overview

Description

The VIAS control solenoid valve 2 plays a crucial role in managing the intake manifold vacuum signal for power valve 2 control. It responds to ON/OFF signals from the ECM (Engine Control Module). When the solenoid is OFF, the vacuum signal from the intake manifold is cut, and when the ECM sends an ON signal, the vacuum signal is directed to the power valve actuator 2.

DTC Logic

To understand the Diagnostic Trouble Code (DTC) logic associated with P1801, a series of tests are conducted to confirm the presence of the code. These tests involve specific conditioning and confirmation procedures, aiming to identify potential issues with the VIAS control solenoid valve 2.

Diagnosis and Solutions

Testing Conditions

Before initiating the diagnosis procedure, it is essential to ensure that the battery voltage is above 11 V at idle. This sets the stage for accurate testing conditions.

Diagnosis Procedure

  1. Check VIAS Control Solenoid Valve 2 Power Supply Circuit
    • Turn ignition switch OFF.
    • Disconnect VIAS control solenoid valve 2 harness connector.
    • Turn ignition switch ON.
    • Check the voltage between VIAS control solenoid valve 2 harness connector and ground.
    Is the inspection result normal?
    • YES: Proceed to the next step.
    • NO: Repair open circuit, short to ground or short to power in harness or connectors.
  2. Check VIAS Control Solenoid Valve 2 Output Signal Circuit for Open and Short
    • Turn ignition switch OFF.
    • Disconnect ECM harness connector.
    • Check the continuity between VIAS control solenoid valve 2 harness connector and ECM harness connector.
    Is the inspection result normal?
    • YES: Move on to the next step.
    • NO: Repair open circuit, short to ground or short to power in harness or connectors.
  3. Check VIAS Control Solenoid Valve 2
    • Refer to EC-1432, “Component Inspection.”
    Is the inspection result normal?
    • YES: Proceed to the next step.
    • NO: Replace VIAS control solenoid valve 2.
  4. Check Intermittent Incident
    • Refer to GI-42, “Intermittent Incident.”
    Inspection End

Insights from Nissan Murano Owners

In addition to the technical aspects of P1801, insights from Nissan Murano owners shed light on real-world experiences with related issues. These include maintenance messages, jerking during acceleration, and concerns about the transmission. Addressing P1801 may involve a strategic approach, beginning with the replacement of the VIAS valve solenoids and potentially extending to transmission considerations.

Nissan Maxima 3.5 – Additional Codes and Considerations

P1800, P0868, and Diagnostic Guidance

The 2009 Nissan Maxima 3.5 presents additional codes, namely P1800 and P0868, each carrying its own set of implications. The P1800 codes are specifically tied to the VIAS valve, suggesting a high failure rate and recommending the replacement of both solenoids located under the intake manifold assembly.

P0868 – Internal Transmission Code

The P0868 code raises concerns about the internal transmission, historically necessitating a full transmission replacement when triggered. Prioritizing the resolution of P1800 and P1801 before addressing P0868 is advisable, as solving the solenoid issues might alleviate the need for a transmission replacement.

Real-world Challenges and Owner Queries

Nissan Murano owners share their challenges, ranging from maintenance messages and jerking during acceleration to concerns about engine longevity. These real-world scenarios highlight the diverse issues faced by vehicle owners and the importance of addressing OBD-II trouble codes promptly.

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