We all should know by now that our bikes don't have OBD ports; instead we have that nifty little DLC connector under the seat... Honda's proprietary DataLink Connector. But what is it, how do we use it, and what can it give us?

WHAT IS IT
Under the seat on the bike... and on page 26-12 of the manual, with it's four positions connected as such:

i. a black\yellow wire that goes to another 14 position connector... purpose unknown
ii. an orange\white wire that goes to an ECM pin called "K-LINE"... purpose unknown
iii. a green ground wire
iv. a brown wire that goes to an ECM pin called "SCS"... likely the datalink to the ECM since SCS is what DLC was previously called





HOW DO WE USE IT
The ECM is hard coded with our ignition timing and injector fueling tables. The ECM reads in sensor data, and depending on what the sensors say, it chooses an appropriate timing and fuel table. Further, these tables are spread over two separate maps... one for low-throttle-low-load and one for high-throttle-high-load.

The Honda dealer techs use a tool called HDS (Honda Diagnostics System) to view engine control data. There's a version of this tool made specifically for "powersport" vehicles... marine, ATV, and motorcycles... and this actually looks like a great tool. You can read detailed DTC info and use a freeze function where it captures the state of sensors at the exact moment a DTC occurs. You can clear DTC's and perform an ECM reset. You can view all inputs to the ECM as well as all outputs. You can setup a trigger event and record up to three minutes of data after the trigger to help diagnose intermittent problems. You can perform system health checks. And a few more things. Unfortunately... I *think* you need to be a dealer and have a dealer number to use this... can anyone advise me on this?

I'm currently looking into another tool from Healtech called OBD-Tool. I don't know much about this yet... but at the least it does have the ability to monitor the inputs and outputs.








WHAT CAN IT GIVE US
I wondered for a long time what data was available at the DLC... and I *think* I found the answer. The HDS user guide says all inputs and all outputs of the ECM are available on the DLC port... which would mean everything listed below can be read... but I still have a few questions. I may just bite the bullet and get the Healtech tool but I think that needs to be connected to a laptop wheres the HDS is a standalone. Let me know if anyone here has an HDS... or knows of someone who is not a dealer who is using one.

- ignition timing... average? for each cylinder?
- injector pulse width... average? for each cylinder?
- fuel pump control
- fan control

- MAP (manifold absolute pressure)
- BARO (barometric pressure)
- ECT (engine coolant temperature)
- TP (throttle position)
- IAT (intake air temperature)
- VS (vehicle speed)
- CMP (camshaft position)
- CKP (crankshaft position)
- GP (gear position)
- right O2 sensor... malfunction indication only?
- left O2 sensor... malfunction indication only?
- right knock sensor... malfunction indication only?
- left knock sensor... malfunction indication only?
- IACV... malfunction indication only?