Hi,
The evap system vapor pressure obd reading is with negative - 70 psi at idle and - 400 to - 600 psi while driving . Is this normal
China car around 85 k miles 2022 year
No code except P0420
Low power but all obd reading is fine.
Not only isn't it normal, it's impossible.
You must mean those readings are in inches of Mercury (inHg), not PSI.
That -0.400 inHg to -0.600 inHg vacuum while driving can only be explained by the Vent Valve being closed as the Purge Valve is being commanded open by the computer. That should only happen when the computer is performing a self test on the EVAP system for leaks.
So maybe check for a clogged/stuck closed EVAP Vent Valve
China car around 85 k miles 2022 year
No code except P0420
then it could still be covered under emissions warranty. Read your warranty booklet.
The evap system vapor pressure obd reading is with negative - 70 psi at idle and - 400 to - 600 psi while driving . Is this normal
Is there a check engine light? Your vent valve could be stuck open. That's excessively high while driving and idling. At sea level, a perfect vacuum would be -14.7 PSI. Did you accidentally hit two keys, not one?
