2000 Honda Isuzu Rodeo with P1441, P1290, and P0300 Codes: Diagnosis and Catalytic Converter Vibration Issues

The vehicle is a 2000 Honda Isuzu Rodeo — technically a shared platform between the two brands. Regarding P1290, it's not related to coolant temperature but rather an electronic throttle control fault. P1441 indicates an issue with the evaporative emissions system. These codes are distinct and may point to different underlying problems. It’s important to understand what each code means before replacing parts.

P1290 is actually a fault related to the Electronic Throttle Control (ETC), not the coolant temperature sensor. P1441 points to an evaporative emissions system malfunction. Many auto parts stores, such as AutoZone or Advance Auto Parts, often misdiagnose these issues and recommend parts based on code readings alone — without proper diagnostic tools or vehicle-specific data. Simply reading a code doesn’t mean the part is faulty. A full diagnosis with real-world data is essential to avoid unnecessary spending.

I clarified that my vehicle is a Honda Passport, which shares its platform with the Isuzu Rodeo and features a Honda badge. I initially bought the water temperature sensor from Napa Auto Parts. A week later, I visited AutoZone to clear the codes (by pressing a button), but the check engine light returned within three days. I then went back to AutoZone to get a printed report of the current codes.

No intention to criticize — just frustrated with how many parts stores diagnose vehicles instead of actually fixing them. How does your car perform in terms of throttle response? Is it smooth and responsive under normal driving conditions?

Thanks for the feedback! I appreciate the input. The throttle response is generally good, but there have been a few instances where the idle drops to dangerously low levels — causing the engine to stall — and occasionally it runs too fast for a short period. These symptoms may be linked to either an electronic throttle issue or misfire problems.

I completely agree with Ascemt. Auto parts stores are primarily in business selling parts, not diagnosing vehicles. Even if the code reader correctly identifies a fault, aftermarket sensors often have poor quality and fail prematurely — leading to wasted money. It's far better to invest in professional diagnostics by a qualified technician or use tools like NAPAFIX, IATN, or D-Tips to check for known technical service bulletins (TSBs) before purchasing parts. Most dealerships follow this practice, which is why they often resolve issues correctly the first time. While some users may have strong opinions about dealerships, it's worth noting that many of them do employ competent technicians who prioritize accurate diagnosis over part sales.

A malfunctioning electronic throttle body could indeed explain the symptoms you're describing — such as erratic idle or sudden acceleration. While a simple cleaning or recalibration might help, full recalibration typically requires dealer-level tools and access to vehicle-specific software. It's also worth noting that used car lots often employ less experienced technicians, which can lead to poor diagnostic outcomes.