OBD2 , SCS, ABS/VSA

Glossary

ECU = Electronic Control Unit
ECM = Engine Control Module (aka engine ECU)
PCM = Powertrain Control Module (infers auto-gearbox but sometimes ECM/PCM written and infers just ECM)
DTC = Diagnostic Trouble Code
OBD2 = On-Board Diagnostic version 2
SCS = Service Check Signal (Honda cable for instigating flashing lights in the instrument cluster)
CAN or CANbus = Car Area Network bus
VSA = Vehicle Stability ***ist (aka ESC - Electronic Stability Control)
ABS = Anti-lock Braking System (not the same as cadence braking)

Using OBD2

The 7th (and 8th) gen Accords have multiple ECU's which communicate on the Honda CAN. Several of the ECU's can 'self-diagnose' with their own DTC's which can be read from the 16-pin OBD2 socket (or by use of the SCS, see next post).

The DTC's from the ECM/PCM begin with the letter "P" and are known as "P codes" and it should be noted that OBD2 is a global 'standard' for getting "P codes" only

i.e. most low-cost OBD2 readers will read DTC's from any engine ECU on any car made after ~2002 , but will give spurious or no DTC's from other ECU's.

Here is the pin-out of the standard OBD2 socket


--The red and grey are for power to the OBD2 reader/scanner

--The green are for connecting directly to CANbus (no connection on the 7th gen)

--The yellow are K-line (pin 7) and L-line (pin 15) which are both RS232 derivatives.

--The blue are a Ford/GM protocol (no connection on the 7th gen)

Low-cost generic OBD2 readers and hand-held scanners use the ELM327 interface --> https://en.wikipedia.org/wiki/ELM327 which can only read fully compliant OBD2 interfaces/protocols i.e. it will read "P codes" using any of the comms lines installed between the OBD2 socket and the engine ECU.

There are ultra cheap ELM327 devices available on eBay that will work with a smart-phone. If you have an Android phone search for "ELM327 Bluetooth" (without quotes), or "ELM327 WiFi" if you have an Apple phone. Best to use "advanced search" and select "Buy It Now" and select "Located In United Kingdom". They cost under £5 . You'll also need an app for the phone. This will be able to read and clear all engine codes on any car made after ~2002.

If you want to be able to read the "P codes" and the DTCs from the ABS/VSA unit via the OBD2, search for "Honda ABS scanner" which currently brings up the iCarsoft i990 and the Foxwell NT510.
Note that if you search for "ABS scanner" in ebay, you may find others that claim to read Honda ABS in the small print.

Finally, the cheapest way to 'access' all ECUs in the 7th gen, is to buy a cloned HDS/HIM (Honda Diagnostic System / Honda Interface Module). Search for "Honda HDS HIM" in eBay. Note the HDS software runs in Windows XP and can be difficult to set up , see --> http://typeaccord.co.uk/forum/topic/21097-honda-hds-nightmare/

Using the Honda SCS

Honda used to fit a 'flying lead' with a 2-pin plug on the end, but on the 7th gen Accord it is a socket in the under-dash fuse-box. The socket resembles an RJ45 but fortunately they also brought the wiring out onto pin 9 of the OBD2 socket.

You can read engine DTCs and ABS/VSA DTCs by shorting pins 9 and 4 with a wire or a paper-clip (make sure that you get the correct orientation of the OBD2 connector, pin 9 should have a brown wire connected to it, pin 4 should have a black wire connected to it) . Then look at this youtube video starting at this point, using pins 9 and 4 on the OBD2 connector instead of the SCS flying lead --> https://youtu.be/8M5BaAa6tCM?t=5m23s and then play the video for a further 4.5 minutes until 10:00

Once you have the codes, see here --> http://typeaccord.co.uk/forum/topic/23513-vsa-to-be-or-not-to-be-that-is-the-question-lol/?p=244588

To clear the ABS/VSA codes see here --> http://typeaccord.co.uk/forum/topic/23396-abs-vsa-fault-anybody-got-any-advice-please-cos-i-wanna-scream/?p=242991 which includes a method for solving VSA DTC 84

Note that VSA DTC 66 is known as the "code of doom" for the VSA, as it will require open-heart surgery.

Note that, since 2013, both ABS and VSA have been part of the MOT --> https://www.mot-testing.service.gov.uk/documents/manuals/m4s03000401.htm

Also, note that on the diesel car the entire braking system (ABS modulator and calipers) is ATE , which is a German hydraulic brake company started 100 years ago by Alfred TEves , now taken over by Continental --> https://en.wikipedia.org/wiki/Continental_Automotive_Systems

The ATE modulators tend to give more problems than the Nissin modulators (the entire braking system on the petrol models is Nissin). But even the Nissin modulators can give the "code of doom".

Finally, on the 7th gen Accord ....

VSA was never fitted to any pre-facelift 2.0
VSA was always fitted to all pre-facelift 2.4
VSA was always fitted to all pre-facelift 2.2 Exec
VSA was optional on pre-facelift 2.2 Sport

VSA was optional on all facelift 2.0
VSA was always fitted to all facelift 2.4
VSA was always fitted to all facelift 2.2

for more info on the above list see --> http://typeaccord.co.uk/forum/topic/23513-vsa-to-be-or-not-to-be-that-is-the-question-lol/

for more info on the way the Honda VIN describes the car's spec see here --> http://typeaccord.co.uk/forum/topic/23517-honda-vin-numbers/

Very good info.cant beat the paper clip method.
I brought an icarsoft i990.its ment to read dct codes.but it wont.but it will clear them.bit weird

Vsa is pointless

Holy crap freddo, that is one hell of a sticky lol
Finally all the relevant info on vsa etc in one area.
I tip my cap to you sir

Oh no I've run out of likes !

ukcl9 said:

Very good info.cant beat the paper clip method.
I brought an icarsoft i990.its ment to read dct codes.but it wont.but it will clear them.bit weird

Vsa is pointless

Click to expand...

that i990 does odd
yeah VSA is rubbish, I always turn it off, wasn't installed on pre-facelift CL7 , makes you wonder why it was on any of them, it's probably a marketing gimmick

Andyjdmteg said:

Holy ***** freddo, that is one hell of a sticky lol
Finally all the relevant info on vsa etc in one area.
I tip my cap to you sir

Click to expand...

it was mainly copy and paste (into Word to start with) just as you said here --> http://typeaccord.co.uk/forum/topic/23540-vsaabs-showing/?p=244902

Andyjdmteg said:

Oh no I've run out of likes !

Click to expand...

gets annoying after a while LOL

The cl7 euro r has no vsa

one more reason to buy a euro r