Many Kia Sedona owners looking to diagnose their vehicles encounter a common challenge: accessing the Engine Control Unit (ECU) fault codes. While the standard 16-pin OBD2 port, conveniently located inside the vehicle, works perfectly for basic live data monitoring with tools like ELM327 Bluetooth devices and apps like Torque or Piston, it often falls short when it comes to reading deeper diagnostic trouble codes from the ECU. This is where the 20-pin diagnostic port, typically found under the hood, comes into play.
For those familiar with OBD2 diagnostics, the natural solution is to use a 20 Pin To 16 Pin Obd2 adapter cable. These adapters are readily available online, promising to bridge the gap and allow standard OBD2 scanners to interface with the 20-pin port. However, as many users have discovered, simply plugging in an adapter doesn’t always guarantee success.
One common issue reported is that while the ELM327 Bluetooth device powers up and pairs successfully when connected via the 20 pin to 16 pin OBD2 adapter, it fails to establish communication with the ECU to read fault codes. This suggests that the problem isn’t with the OBD2 scanner itself, but rather with the adapter cable or the 20-pin port connection.
The suspicion often falls on the wiring of the 20 pin to 16 pin OBD2 adapter cable. If the adapter is incorrectly wired, it won’t properly map the signals from the Kia’s 20-pin diagnostic port to the pins required by a standard 16-pin OBD2 scanner to communicate with the ECU.
To investigate this further, it’s helpful to understand the pinout of the Kia 20-pin diagnostic port. While finding a definitive and accurate pinout diagram can be challenging, especially one that perfectly matches every Kia model and year, some users have attempted to map the populated pins using a voltmeter. Voltage readings on the 20-pin connector with the ignition on (engine off) can provide clues about power and signal pins.
For example, one user reported the following voltage readings on their Kia Sedona’s 20-pin diagnostic port:
- Top Row: Pin 1: 0V
- Middle Row: Pin 5: 0V, Pin 8: 11V, Pin 9: 2.6V, Pin 12: 12V
- Bottom Row: Pin 15: 12V, Pin 17: 2.4V, Pin 18: 10V, Pin 19: 6.4V
These readings highlight that only a subset of the 20 pins are actually populated and active. The challenge then becomes matching these active pins to the correct pins on the 16-pin OBD2 connector through the adapter cable.
The frustration arises when generic 20 pin to 16 pin OBD2 adapters fail to work out of the box. Unlike some Daewoo vehicles where ELM327 devices can readily read all data and clear codes via the standard OBD2 port, older Kia models might require accessing the 20-pin port for comprehensive diagnostics, including ECU fault codes.
Therefore, troubleshooting a non-working 20 pin to 16 pin OBD2 adapter often involves:
- Verifying the adapter wiring: If possible, obtain a reliable pinout diagram for the Kia 20-pin diagnostic port and compare it to the wiring of the adapter cable. Check if the essential pins for ECU communication are correctly mapped to the 16-pin OBD2 connector.
- Testing with a multimeter: Use a multimeter to check continuity between the pins of the 20-pin connector and the corresponding pins on the 16-pin connector of the adapter cable. This can help identify any broken or incorrectly connected wires within the adapter.
- Seeking pinout information: Continue searching for accurate and verified pinout diagrams specifically for your Kia Sedona model and year. Online forums, repair manuals, or automotive diagnostic resources might provide valuable information.
Successfully using a 20 pin to 16 pin OBD2 adapter hinges on ensuring correct pin mapping. Without the proper wiring, communication with the ECU for reading fault codes will likely fail, even if the OBD2 scanner powers up. For Kia Sedona owners and similar vehicles with 20-pin diagnostic ports, understanding the pinout and verifying the adapter cable wiring is crucial for effective vehicle diagnostics.
