The OBD2 (On-Board Diagnostics II) port is a crucial interface in modern vehicles, serving as a gateway for diagnostics, programming, and performance tuning. Pin 16 of this port is specifically designated to provide battery voltage, acting as a power source for various OBD2 devices. When you encounter issues with devices that rely on this power, such as tuners or scan tools, understanding and troubleshooting pin 16 voltage is essential.
One common problem arises when there’s a discrepancy in voltage readings, or a perceived lack of power at pin 16. Let’s delve into a real-world scenario and explore how to diagnose such issues.
A user recently reported experiencing problems with their Livewire TS tuner. They observed voltage drops throughout the vehicle’s cab, excluding directly at the battery terminals. After noticing the tuner malfunction, they investigated the voltage at OBD2 pin 16.
Using a multimeter directly on pin 16, they measured a healthy 13.6 volts with the key off, and 12.6 volts with the key on (after glow plugs cycled). Under glow plug operation, the voltage dipped to around 11.6 volts, all within a normal range for battery voltage in a vehicle. This suggested that pin 16 was indeed receiving power from the battery.
However, the Livewire TS tuner displayed a significantly lower voltage reading (11.3 volts) compared to the multimeter’s reading of 13.6 volts taken simultaneously at pin 16. This discrepancy occurred specifically after attempting to change the vehicle’s tune. Before attempting the tune change, the Livewire TS correctly mirrored the multimeter reading of 13.6 volts.
This observation points towards a potential issue within the Livewire TS device itself. Despite receiving proper voltage at pin 16, the tuner’s internal power circuitry might be malfunctioning, causing an inaccurate voltage reading and hindering its operation.
This case highlights a crucial troubleshooting step: verifying voltage directly at pin 16 with a multimeter when encountering OBD2 device power issues. If the multimeter readings are normal, but the OBD2 device indicates low voltage or malfunctions, the problem may lie within the device itself, rather than the vehicle’s OBD2 port power supply.
In conclusion, when diagnosing power-related problems with OBD2 devices, always start by confirming the voltage at pin 16 using a multimeter. A proper voltage reading there, contrasted with device malfunction or low voltage readings on the device, can pinpoint the source of the issue, potentially saving time and directing focus towards the problematic OBD2 device.
