P0446 after Right-Rear Collision & Refuel - Gen 2 Prius (2004) - Rough Idle/Start Body:

Hi everyone,

I'm looking for technical advice on a persistent P0446 code on my 2004 Toyota Prius (Gen 2). The history of this fault is quite specific:

1. The Incident: About 5 weeks ago, the car was rear-ended on the right side. The impact damaged the right rear light housing and slightly compressed the area housing the 12V auxiliary battery.

2. Delayed Symptoms: After the body repairs, the car ran fine for about a month. However, I started noticing:

• Decreased Fuel Economy: A significant drop in MPG.
  
  
• Frequent Cycling: The ICE (Internal Combustion Engine) started cycling on and off much more frequently than usual.
  
  
• Rough Transitions: The transition from EV to ICE became very jerky, with pronounced vibration/shuddering upon engine startup.
  

3. The Trigger: A few days ago, shortly after a full refuel, the Check Engine Light finally illuminated with code P0446 (Evaporative Emission System Vent Control Circuit).

My Analysis & Questions: Given the right-rear impact, I suspect the Charcoal Canister or its associated Vent Valves/Vacuum lines (located near the rear) might have sustained a hairline crack or loose connection that only manifested as a hard fault after the pressure change of a refuel.

• Has anyone experienced a rough engine start/stop specifically tied to an EVAP circuit fault?
  
  
• Could a hairline crack in the canister cause these hybrid system driveability issues before the CEL even triggered?
  
  
• Should I focus my inspection on the CCV (Canister Closed Valve) or the fuel filler neck area?
  

Any insights from the community would be greatly appreciated. Located in a high-temperature climate (Phnom Penh), which might be stressing the plastic components.

Thanks in advance!