Troubleshooting 4WS (DTC codes) - Honda Prelude Forum

4thGenReady2Go · 07-04-2005, 09:30 AM

no, i don't have 4ws, I wish I did

Trying to help a guy out, his 4WS malfunction indicator is coming on. I read through my Service Manual's section on troubleshooting 4WS and getting DTC codes, but the description left a little to be desired (for my anyway). Am I to understand that the 4WS codes are retrieved the same way a MIL/CEL code is?
The diagram of the 4WS code output is kind of confusing, all I got out of it was there are pauses of different lengths or something as the light blinks on and off. If someone who has 4WS has the slightest idea of what I'm talking about, I'd appreciate any help you can offer.

4thGenReady2Go · 07-05-2005, 11:49 AM

any ideas?

SoFlaLude · 07-05-2005, 01:40 PM

Yep, I've got 4WS and the way to get the error codes is the same as ECU error codes: short the service connector behind the radio with a paper clip, turn the key to the Accessory position and count the number/duration of each blink of the 4WS light in the dash and look that code up in the Helms manual. 4WS can be a tempermental little beast when it wants, and if there are any actual problems it could cost serious cash to fix. I'd look the codes up, see what they are, erase the error codes from the system's memory (this I'm rusty on, I can't remember if the 4WS ECU would be erased at the same time with the regular ECU by removing the radio fuse, or if you had to yank the 4WS fuse too), drive some, and if the error comes back check which code it's throwing again.

mtbprelude · 07-05-2005, 02:09 PM

There are several fixes, some are temporary, some seem to be more permanent.

In my case my 4ws light came on at startup for over a yr before some one told me to just re-engage the starter once the engine was on. (Yes it makes a bad noise) I did this for over 3 yrs before recently that no longer fixed it. I haven't had time to disassemble the 4wsECU, but I believe there are some really good write-ups on H-T for troubleshooting that component: Link to this

1. Disconnect battery
2. Remove 4WS unit from car (before to get access you have to take off left rear seat and rear moulding inside trunk): disconnect 3 (If I remember well) connectors, 1 or 2 grounds, remove metal cover, and finally remove the unit.
3. Open 4WS unit (6 screws) and carefully put the cover (there is an electronic board connected with one electrical stripe) on the side. I used a big large book to put the cover on and not to brake the stripe. Finally you will have cover on the left side (laying on the book) and open 4WS unit on right side.
4. Remove internal metal cover you will see on the right side (some screws) and take it off.
5. You will see a lot of electronical (and electromechanical) parts inside. There are two black boxes (about 1 cm x 1.5 cm) little under the center of the unit. These boxes are 2 small relays. The problem is there!!! , but on the other side of electronic board, so next step is....
6. Remove the main electronic board from the box: remove all screws that fix the board to the box and other components: I am unable to say you exactly how many of them you have to unscrew - I just don't remember, but you will see yourself what is keeping the board in place. Also it is necessary to unscrew 8 big transistors from box (serving as radiator).
7. When the board is unscrewed, put some protecting paper (ex. newspaper) on the cover board laying on the book and carefully extract the board from aluminium box. Put it on the newspaper with solderings side upper.
8. These 2 relays are soldered 4 or 5 points every of them. These are big solderings. I took a magnifing tool (don't know exact english name - zoom ???) and carefully watching the relays solderings I considered ALL of them were broken.
9. Resolder all relays points and mount the unit.
10. After reputting it in the car problem's GONE!!!!