4ws ECU Repair - 4th gen

Post by **vanzep** » Mon May 27, 2024 9:06 pm

My 4th gen BB1 has started to get a 4ws light coming on. It is only every so often and when restarting the car when the engine is hot. If I turn the engine off and restart it the 4ws light goes off. So am I correct in thinking this will be dry solder joints in the 4ws ECU in the boot? and is not related to the main relay. Is there a guide on how to resolder the ECU?
Any help appreciated as I would like to get this fixed before it goes for its MOT next Tuesday.

Scott560 · Post by **Scott560** » Tue May 28, 2024 9:03 am

I seem to recall well before my honda ownership, I helped someone do an H22 engine swap between 2 4th gens. They had both main relay failure, and 4ws failures.

The cold/cracked solder joints were all along the main power connectors, no where else. Even with relatively little electronics knowledge, you can most likely fix it with a beefy iron and some flux/fresh solder. If you only have a normal soldering iron (mains powered 25watter) you probably won't have a good time.

If you are not confident with soldering, you should be able to take it to any electronics repair place - even if they don't know the ECU or car or how to test it, they will be able to reflow the joints on the main connectors and switching semiconductors (which is where most of the solder mass is and takes the most stress mechanically and from heat, hence the cracking).

I'm sure there is probably a guide on youtube?

Post by **Vtecmec** » Tue May 28, 2024 9:11 am

Yes, nothing to do with the main relay, and it could be the solder joints in the ECU. It could also be something else, have you pulled the codes?

Here is a good guide:

https://www.preludepower.com/threads/4w ... 8/#replies

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue May 28, 2024 1:33 pm

Definitely pull the codes first.
If it is related to needing solder repair, then that repair in itself is pretty simple/straight forward tbh. The most difficult bit is disconnecting/removing the ECU from the boot (not technically difficult, just awkward).

Post by **vanzep** » Tue May 28, 2024 9:16 pm

Thanks for the input guys - much appreciated.
Ive owned the BB1 since 2015 but Ive never pulled a code from it. I know how to get the codes for non 4ws 4th gens but I probably need to read up on the 4ws side of things. I will see if there are any codes stored tomorrow.
Sure I have a spare 4ws ecu somewhere so if needed I can try out the solder repair on that first.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed May 29, 2024 1:34 pm

You get the codes in exactly the same way - there's only the one service connector.

Post by **vanzep** » Fri May 31, 2024 6:48 pm

Ive found the link to 4ws error codes in the knowledge base on the forum

so im away to pull the code now.
kb/viewarticle?a=2

Post by **vanzep** » Fri May 31, 2024 7:17 pm

Ok ive pulled the codes.
4ws light flashes code 62 - 4ws power unit motor
also I have TCS light flashing code 49 ......... any idea what this might be? cant find any info on this.
Just to clarify i am NOT getting a tcs warning light on the dash only 4ws so bit of a surprise to get a tcs code when jumping the connector - guessing it could be related to the intermitent 4ws warning light on speedo?

What a pain and with MOT on Tuesday morning

Post by **Vtecmec** » Fri May 31, 2024 8:32 pm

I'd try checking and cleaning the large power connectors on the rear steering motor, the ones that sit under the large rubber cover.

Also probably worth checking and cleaning any other electrical connectors whilst your down there too.

Hagland-BB4 · Post by **Hagland-BB4** » Fri May 31, 2024 10:51 pm

Those lights will not affect an mot