OBD-II Diagnostic Tools

 

TL;DR As a wise man once said... "Everything's computer !"

Yes, that's true. Everything is computer. Even on unsuspecting modern Caterhams, a computer is in charge of the engine management, but also the complete dashboard. See the post about the chassis harness on the ECU for far too much more. 

Anyway, one obvious feature is the engine light on the dashboard, the one that tells you that something needs to be looked at, or that something out of the ordinary happened.

For most people, this means getting an appointment and have the mechanic look into that. Most of the time with a Caterham, people live quite far away from their dealer.

A convenient way to get a first clue of what's happening is a OBD-II  scanning tool (sometimes written as OBDII or OBD2 - OBD standing for On Board Diagnostics)

I have personally been using a cheap ELM327 bluetooth dongle for probably a decade at this point, driving a MG and all that... It's compact and connects to the Torque PRO app on my phone (compact black and orange one on the picture above). 

It is so cheap and useful that I keep a one in every car now (blue v2.1 "mini" ELM327 on the picture above - We're talking 2.29€ cheap).

With those, I can scan for error codes, have some basic explanation of what the engine is complaining about, clear everything to see if the error comes back, turning the engine light off as well.

Troubleshooting the MG with a new MAF sensor and confirming with error code "P0674" that something was wrong with a glow plug on the Skoda come to mind. I'm not sure I ever solved anything with the KIA EV, but it's fun to see the voltage and status of each of the hundreds of battery cells.

Over the first few months with the 170S, 2 occurences of over-enthusiastic on/off use of the gas pedal led to an engine warning light kicking in : "P0102 - Mass or Volume Air Flow Circuit Low Input" and "P2563 - Turbocharger Boost Control Position Sensor Circuit Range/Performance". All my fault, nothing wrong with the car, they were cleared and never came back.

But you can imagine how stressful it could be to have an engine warning light coming on for no apparent reason, have having to drive an hour to the deaker to have it checked.
For instance when a rubber bung gets away from the intake plenum, error "P0172 - system too rich" arises. That one can be identified without OBD as the warning light confirms that the idle is unstable, and it's readily apparent than a rubber stopper is missing when you know what you are looking for.

Another feature of the OBD port are live readings of all that's going on with the engine. RPM, MAF airflow, coolant temperature, intake temperature, intake (turbo) pressure, battery voltage ... the list goes on.
That's how I was able to know out the turbo performed before and after the upgrade, as well as confirm the intercooler air guide was doing its job very well indeed.

Out of curiosity I also got a "K310" OBD scanner, in bright yellow. It's also powered by the OBD port, does the job perfectly fine but I find the interface on the small LCD display less efficient to read real time data. It's quite large too. I can see it being less initimdating than a bluetooth dongle and a smartphone app. That one was just 14€ or so.

Note that all ELM327 clones are not guaranteed to work well, expecially v1.5 that are sometimes not compatible with Torque PRO. Some  BLE (bluetooth low energy) alternatives are also available.