OBD-II Code
P0490
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$90–$380
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0490 reports the EGR vacuum regulator solenoid control circuit voltage is high, indicating an open circuit, a disconnected solenoid, or a PCM driver issue on the high side.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0490 reports the EGR vacuum regulator solenoid control circuit voltage is high, indicating an open circuit, a disconnected solenoid, or a PCM driver…
P0490 reports the EGR vacuum regulator solenoid control circuit voltage is high, indicating an open circuit, a disconnected solenoid, or a PCM driver issue on the high side.
Cheapest checks first
- confirm the EGR vacuum solenoid connector is fully seated and the harness is intact, then measure solenoid resistance across the terminals, which is typically 20-45 ohms on most domestic applications and 25-35 ohms on Toyota/Honda VSV-style solenoids.
- Verify the PCM-side circuit shows 12V key-on at the supply pin and a PCM-driven ground at the control pin under commanded EGR flow conditions.
- The expensive misdiagnosis is replacing the EGR valve itself ($250-$700) when the inexpensive vacuum solenoid ($40-$120), a corroded connector, or a cracked vacuum line is the actual fault.
Vehicle-specific patterns1999-2004 Toyota Tacoma/4Runner 3.4L V6 (5VZ-FE) EGR VSV fails from diaphragm cracking under heat cycling; 2003-2008 Honda Pilot/Odyssey J35 EGR sole…
- 1999-2004Toyota Tacoma/4Runner 3.4L V6 (5VZ-FE) EGR VSV fails from diaphragm cracking under heat cycling;
- 2003-2008Honda Pilot/Odyssey J35 EGR solenoid connector pin corrodes from engine bay humidity;
- 2005-2010Ford F-150 5.4L 3V EGR vacuum regulator solenoid suffers internal contamination from soot blow-by;
- 2002-2006Subaru Outback/Forester 2.5L EGR solenoid harness chafes against the intake manifold bolt.
Estimated repair$90 to $380.
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