P1490 NISSAN: Code Meaning, Causes, Symptoms, & Tech Notes
Engine-Codes - Nissan - P1490 NISSAN

P1490 NISSAN - Vacuum Cut Valve Bypass Valve

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?

P1490 NISSAN Possible Causes

  • Faulty Vacuum Cut Valve Bypass Valve
  • Clogged vacuum hoses to the Vacuum Cut Valve Bypass Valve
  • Vacuum cut valve bypass valve harness is open or shorted
  • Vacuum cut valve bypass valve electrical circuit poor connection

How is the P1490 NISSAN code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

There is a factory service bulletin for the following Nissan models:

2002 Nissan Altima
2003 Nissan Altima
2004 Nissan Altima
2005 Nissan Altima
2002-2005 Nissan Altima Service Bulletin OBDII Code P1490

What is the cost to diagnose the P1490 NISSAN code

Labor: 1.0

The cost to diagnose the P1490 NISSAN code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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When is the code detected?

An improper voltage signal is sent to ECM through vacuum cut valve bypass valve.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P1490 NISSAN Meaning

The vacuum cut valve and vacuum cut valve bypass valve are installed in parallel on the EVAP purge line between the fuel tank and the EVAP canister.
The vacuum cut valve prevents the intake manifold vacuum from being applied to the fuel tank. The vacuum cut valve bypass valve is a solenoid type valve and generally remains closed. It opens only for on board diagnosis.
The vacuum cut valve bypass valve responds to signals from the Engine Control Module (ECM). When the ECM sends an ON (ground) signal, the valve is opened. The vacuum cut valve is then bypassed to apply intake manifold vacuum to the fuel tank.

More Information

Need more information on how to fix the P1490 NISSAN code?
Get Access to Factory Service Manuals

Information for specific Nissan models

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