Yet another 4WS thread

Anzezaf · Post by **Anzezaf** » Mon Mar 05, 2018 9:22 pm

Hello gents,

I recently bought my first car - a BB8 prelude (185BHP H22A5) with the infamous 4WS system.
Now, some previous owner which I can't get a hold of, disabled the 4WS (god knows why) and I'm interested in getting it turned on again (it's been off for about 3-4 years now).

Where should I start looking / troubleshooting

- There are no 4WS lights on the dash panel
- The proper fuse is inserted in the 4WS slot in the engine fuse compartment

I was thinking about checking for power at the 4WS control module / ECU, but for the life of me i can't find any info about it - Where it is, what voltages should i look for etc..

Or maybe i could check a relay, if I knew where it is / where to look.

Thanks for the help in advance!

EDIT:
5TH GEN 4WS manuals here (same documents, but hosted twice for redundancy):

https://drive.google.com/drive/folders/ ... 3pST1Z5VGM

https://drive.google.com/drive/folders/ ... sp=sharing

no0ne · Post by **no0ne** » Mon Mar 05, 2018 9:43 pm

May sound funny, but check if actual bulb for 4ws light is present in your instrument cluster

i know i have removed it when i was out of luck fixing my 4ws, that guy could have done that too if its been disabled for this long. One error is enough for 4ws to shut off, so there may be minor problem. Or else.

Anzezaf · Post by **Anzezaf** » Tue Mar 06, 2018 6:08 am

Hah! Nice idea, will check.

In the mean time, any other suggestions?

Scott560 · Post by **Scott560** » Tue Mar 06, 2018 8:10 am

the bulb should illuminate when the ignition comes on. If you don't see 4WS then the bulb is gone or removed...

The ECU is in the boot, on the drivers side. Pretty sure there is a related relay on a bracket nearby to, which clicks when the 4ws turns on after engine starting.

Check the previous owner also hasn't inserted the locking pin into the rear rack.

You wont be able to do a 4WS reset without the light working (as it gives you timings to do certain actions).

Anzezaf · Post by **Anzezaf** » Tue Mar 06, 2018 8:32 am

Right, thanks a bunch

Will report back as soon as I get the chance to work on it.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Mar 06, 2018 8:51 am

Welcome
Yes, you definitely need to get the system fixed, or properly removed it not - it's not designed to be driven with it just 'isolated'since the only things holding the rear wheels straight, are a couple of springs. In hard cornering/on ruts/bumps in the road the rear wheels will wander slightly.
As others have said, check the bulb is fitted/not blown - that's the first place to start and then pull the codes stored in the system.
Also check on the rack to see if someone has fitted a bit in the central locking pin hole (this should be used for alignment only, not meant to lock the rack off for isolating purposes).

The 4g service manual (can be downloaded via a link in the wiki section) will give you some useful info on the general principles of the system, albeit some of the sensors and the ecu are different in the 5g.

Some geezer recently posted up that he had a copy of the 5g 4ws section, so drop him a pm and ask him to email the manuals to you maybe?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Mar 06, 2018 8:52 am

http://www.ludegeneration.co.uk/chassis ... 19351.html
Link to the guy with the 5g 4ws section from the manual ^^^^

AeroNotix · Post by **AeroNotix** » Tue Mar 06, 2018 9:54 am

I've recently had to get mine back from the dead which required a lot of messing around and debugging.

As others have mentioned. Check that the bulb is actually working.

On 5th gens the 4ws ECU is in the boot. Right hand side. Remove the trim/etc to find it.

Once you know the bulb and ECU exists then there are specific test procedures for certain codes. You would need to grab the error code from the 4ws bulb flashes.

AeroNotix · Post by **AeroNotix** » Tue Mar 06, 2018 10:00 am

Btw I have the 5th gen manual 4ws section but it's in Polish. I have a lot of sections translated. I posted them in my 4ws thread.

Anzezaf · Post by **Anzezaf** » Tue Mar 06, 2018 3:58 pm

Yeah, you guys were right. The bulb was missing, so i switched places with the green key light and now I have a steady 4WS light on.

Will short the service connector ASAP in the following few days and report back.

But, as far as I know, there isn't much one can do apart from the reset/calibration procedure? Sensors are probably next to impossible to find, lock pins have a ghastly price to them etc...