OBD2 Setup: KrispyGauge in a Standard Road Car

KrispyGauge works in a standard road car by reading data through the OBD2 port — no aftermarket ECU needed. Setting it up is different from an aftermarket ECU install in two ways: how you wire it, and what to expect from the data.

Will it work on my car?

Your car needs to use CAN for OBD2 (ISO 15765-4). Broadly, most cars from around 2008 onwards do. Older cars often use K-line or other pre-CAN systems, which aren't supported.

The OBD2 supported vehicles list has the makes and models confirmed working. If yours isn't there it may still work — let us know how you get on.

1. Set the ECU type first

Connect to the Web UI at http://4.3.2.1, go to Settings, and set the ECU type to OBD.

Do this before anything else. Changing the ECU type wipes all your settings — channels, warnings, colours and keypad mappings. Set it first, then build your pages.

2. Wire it to the OBD2 port

The easiest way is our ready-made KrispyGauge OBD cable, which plugs straight in. Otherwise you can splice into the back of your OBD connector.

The OBD2 port is a 16-pin connector, usually under the dash on the driver's side. The pins you need:

• CAN H (yellow) — pin 6
• CAN L (green) — pin 14
• Ground (black) — pin 4 or 5
• 12V (red) — see below

Power needs care. Pin 16 on the OBD port is always live — it doesn't switch off with the ignition. A gauge powered from it stays on when the car is parked and will slowly drain the battery. If you do use it, turn on Sleep mode in the gauge settings to cut power draw and put the screen to sleep when it isn't in use.

We recommend taking 12V from a separate ignition-switched source, such as the radio's accessory feed behind the dash, and using the OBD port only for CAN H, CAN L and ground.

Don't switch on the termination resistor. The car's own CAN bus is already terminated at both ends, and adding another resistor can interfere with the car's electronics.

3. Check for a live signal

Turn the ignition on. Some cars won't respond until the engine is actually running — if you see nothing with just the key on, start the car before troubleshooting anything else.

What to expect from OBD2 data

An aftermarket ECU broadcasts its data continuously. OBD2 is question-and-answer instead: the gauge asks the car for each reading and waits for the reply. In practice that means:

• Slower updates. Fine for coolant temperature and oil pressure, but not the same instant feel as RPM from an aftermarket ECU.
• Fewer readings. You get the standard OBD2 readings your car chooses to share, not everything inside the ECU. Even if OBD2 has a reading for something like oil pressure, your car may not provide it — and there's not much that can be done about that for now.

The OBD2 supported signals page lists every reading KrispyGauge can show over OBD2. For an example of what's possible, see showing ethanol content over OBD2.

Troubleshooting

• No data at all — check the ECU type is set to OBD. Then check pins 6 and 14 aren't swapped, and try with the engine running.
• Worked, then stopped — check whether another device shares the OBD port. Insurance trackers, GPS trackers and diagnostic tools can clash with the gauge. Unplug them and test again.
• Some readings blank — not every car shares every OBD2 reading. A blank reading usually means your car doesn't provide it, not a fault with the gauge.

If your car isn't working and isn't on the supported list, email [email protected] with the make, model and year — it helps us grow the list.