2004 Chrysler Sebring Touring (228,000 km) with P0452 and P0456 OBD2 Codes - EVAP System Diagnosis & Repair Concerns
VEHICLE DETAILS: 2004 Chrysler Sebring Touring, 4-Door Sedan, 2.7L V6 Engine, 4-Speed Automatic Transmission, mileage: 228,000 km. BACKGROUND & ISSUE: During a routine oil change at a service center, I noticed the engine check light was illuminated. The technician recorded OBD2 diagnostic code P0452. I requested a full diagnosis from their facility, which they stated had to be performed anyway. Their initial diagnosis revealed both P0452 and P0455 codes. They advised replacing the Negative Vacuum Leak (NVLD) component, citing this as necessary for proper EVAP system function. The repair cost was calculated at $137: $135/hour rate for diagnosis and labor, plus a 10% tax. Parts and Labor: - EVAP Canister replacement: $251 - Labor (1.5 hours at $203 per hour): $203 - Tax (10%): $40.60 Total repair cost: $500 After the NVLD replacement, the engine check light reappeared on Day 5. I contacted the service center under my 12-month warranty (covering parts and labor for service-related issues) to have it addressed again. Second diagnosis revealed a new code: P0456 — indicating a small EVAP system leak. They claimed that the initial scan could not detect this minor leak, and therefore they now require another diagnostic session at their original $135/hour rate. I expressed concern about the recurring issue and the lack of transparency in diagnosis. I am considering seeking a second opinion from an independent facility. What is your expert insight on P045 or P0456 codes, EVAP system reliability, and whether this constitutes a valid service or diagnostic error? Note: All technical details are accurate and based on actual vehicle data and OBD2 readings.
It sounds like you're dealing with potential inconsistencies in the diagnosis process. P0452 and P0456 both relate to EVAP system leaks — P0452 typically indicates a large leak, while P0456 points to a small leak that may not be detected immediately. The fact that the same issue reappeared after NVLD replacement raises questions about whether the initial diagnosis was thorough or if the repair addressed only part of the problem. A second opinion from an independent technician or dealership with proper diagnostic tools (like a professional EVAP pressure tester) would help confirm whether the leak is genuine and where it's located. When choosing automotive service providers, it's wise to verify their credentials — especially for complex diagnostics like OBD2 codes. Consider asking for references or reviews from other customers, just as you would with any professional service (e.g., doctor, lawyer). A reliable facility should provide clear explanations of each code and the steps taken to resolve them. In this case, if the same issue recurs after a repair, it may indicate either an incomplete fix or inconsistent diagnostic practices. You have the right to seek clarification or alternative services — especially when warranty coverage is involved.