98 Kia Sportage OBD2 Codes List: PO304, PO440, PO451, PO107, P1614 - Car Dies at High Altitude & Won't Start
My 1998 Kia Sportage suddenly died while driving on the road. After that, it will not start and the check engine light remains constantly illuminated. I've already replaced the battery, but the issue persists. When I use an OBD2 scanner, I receive multiple fault codes including PO304, PO440, PO451, PO400, PO300, PO303, PO342, PO107, and P1614. The car exhibits unusual behavior when driving over elevation (6000-7000 ft): it suddenly decelerates from 70 mph to around 45 mph. In city traffic, the check engine light blinks three times when stopped at a red light. I then turn off the engine and restart — during this process, the car does not shake or act like it's about to stall. I've replaced several sensors and components over time, including the battery. The issue began after I turned off the car while waiting for someone and received a jumpstart. A few days later, the car died again while driving. After getting home, I scanned the system and confirmed 9-10 codes. Despite using starting fluid and replacing the battery, the vehicle still won't start. I am a grandmother who cares for my 17-month-old grandson and urgently need this car to run reliably — ideally with no check engine light or fault codes. I'm hoping someone can help me understand what these codes mean and how to fix them. Any advice would be greatly appreciated. Fault Codes: PO304, PO440, PO451, PO400, PO300, PO303, PO342, PO107, P1614
The check engine light was off until suddenly all codes appeared at once — that's concerning. I would prioritize addressing P1614 first, which indicates a voltage issue between the PCM (Powertrain Control Module) and TCM (Transmission Control Module). This is often caused by wiring problems or poor grounding. A DIYer can start by inspecting connections from the battery to the vehicle’s ground points, especially at the firewall where wiring harnesses are prone to damage. My suspicion: All these codes may stem from a damaged wiring harness — particularly in one localized area. If you visually inspect the harness, look for frayed wires or signs of corrosion. This could be the root cause behind both starting issues and erratic performance at high elevations.