EWS-II fault... Repeated problem.

[Omi]

(Pasted from another forum I've asked for help on...)

Hi folks, going to put as much detail as I can in here and hope someone can help.

Fitted M52B28 into my E30 a few months ago. Yes, it goes like a cat with 2 rockets up it's bum...

Donor car was crash damaged and had sat for some time with battery disconnected. - Started fine when reconnected. 2nd time we tried to start it, ignition position 3 (crank) didn't do anything. Locked it all back up, retried. Started fine, thought nothing else of it. - Seller said it was the first time this had happened.

Whole assembly was removed, rewired and reinstalled in the E30. Started 1st time, and was all beautiful.

A few starts later, I got the same failure to respond. Left it a while, retried, all was fine. - Another time I'd turn to Pos3 to crank and nothing would happen for 1/2 a second, up to 5 seconds when it would suddenly decide it was happy and start turning over. The car would intermittently fail to start maybe every 4th attempt.

A month ago the EWS decided it was no longer happy at all... No amount of waiting or retrying would give the characteristic relay click from the EWS module, signalling that the starter would engage and the DME was happy to run.

I swapped out antenna ring, send/receive module and went through all the wiring very carefully and methodically. All was fine. - Went to BMW, spoke to a technician and he said it was likely to be a broken down transponder chip and that I should replace the key... Another key was ordered, arrived and started the car on the first attempt, every attempt.

Until about 4 days later, when the same non-start occurred. Waited, was fine.

Over the last few weeks the same degraded service from the key has been experienced. Exactly like before... This morning I drove to work, an hour later I drove to get some breakfast... Got back in the car with breakfast and failed to start. Have checked wiring again, even tried the old transponder chip. Nothing.

I'm quite familiar with the electronics (having done the swap and wired in the EWS) and the problem is definately not with the starter motor, crank position sensor etc., as I've seen mentioned in similar threads.

When the EWS accepts the key as valid it confirms ISN with the DME and enables injection and ignition in the DME. It also completes the starter circuit, which comprises the audible relay click. As I'm not getting the click, it's pointless searching for faults any further than the EWS-II system.

It's really odd that this has occurred with subsequent keys in exactly the same way over roughly the same time period/number of starts. I seem to recall there are 10,000 rolling code combinations, but is there anything that might run out of combinations after 50-100 vehicle starts? Nothing changed between starting the car successfully and total EWS lockdown on both occasions.

Does anyone understand exactly what an EWS alignment does, have access to GT1/DIS, or have any further information on EWS-II that might account for something I'm missing? Can the code tumblers be reset, or can CarSoft 6.5 align/read key whitelist etc.?

Huge thanks in advance!

Omi

p.s. - Jan '96 built 328i Sport (manual) if req.

[DanThe]

Mine can be a bit slow at times, I think its more about the Toad alarm/immobiliser that is also on the car. Sometimes if I get in and quickly turn the key it wont fire up, just cranks over. But if I turn the key to pos-2 ignition and wait a few seconds (listen for the fuel pump to prime) then turn to pos-3 it fires up every time.
EWS alignment simply allows a matching chip/EWS module to be used with a particular ECU, this could be your next step, trying a different EWS module and chip with your ECU, the eBay carsoft is no good for this though you need to find someone with some proper kit.

Ive got a spare chip/module set if you want to borrow

[Ant]

CS6.5 is all you need to reaslign the EWS

They dont like a low vlotage when cracking, I've seen a few lately where the car refuses to start although will turn over for ages, a Diag reveals a strored fault relating to a sub 10V feed top the EWS module.

I assume you've bypassed the start inhibit Omi ? TBH I only ever fit the 12V main, the 12V switched and the loop back to the ECU, the rest stays hardwired straight through, removes a few problem areas too.

[Omi]

Dan, can you do me a favour if you get a minute?

Swap your EWS unit and transponder chip over... Obviously won't fire the engine, but should still give the relay click on Acc position... If that's the case I can borrow any EWS system off a local friend to confirm wiring is all intact.

IIRC, you've not wired your starter circuit through the EWS, have you? Yours should crank in all instances (Toad notwithstanding) and fuel pump should prime irrespective of EWS. - EWS check with DME to compare codes only activates ignition and injection. Fuel pump remains seperate.

Downloaded the BMW training manual for EWS I, II and III/III-D. Fun reading!

[Omi]

Black/Yellow was already snipped from a previous alarm, so I wired the starter inhibitor relay in. - I bypassed it last month when it failed and it would crank forever, but EWS wasn't accepting the key so was pointless. - Didn't need to reset anything when the key was replaced, just fired immediately, exactly as it should.

It seems like the key is sometimes misread and has eventually been misread enough for the code to be right out of the list of recently acceptable codes... Like the EEPROM in the key isn't getting the new Rolling code.

Is that right, Ant? - EWS keeps a list of valid recent codes and the 10 new key codes. If mine wasn't writing the new codes back to the transponder chip it would eventually drop off the list?

Hmm.

Phoning Ed Kaps at TATS tomorrow morning, will get it recovered there if he knows his beans with EWS.

[Omi]

Ed Kaps didn't inspire a lot of confidence. He didn't quite grasp the swap I'd done and didn't think the OBD2 port would work. - Wanted £40 to try and read the codes and it would mean dragging the car 10 miles to him. - £70 per hour plus parts when he doesn't know what's wrong isn't good for me.

I've bought CarSoft, is on a slowboat from China for £35. Local auto locksmith who has worked with BMWs before with a transponder sensor will tell me whether the antenna ring is broadcasting the 125KHz AM induction frequency.

I'm wondering if there's a bad signal that EWS is deciding "eventually" (maybe after 50 starts) that it doesn't like, and locking down the key. The list of 10 key-codes in the EWS system can go into a BlackList if lost, stolen, tampered...

BMW won't give me the time of day because it's an abomination in their eyes, so I can't get them to check this list. Few folks in BMW dealerships have been asking their techs, but so far no-one's really come back and said "Yes, I've had that before, it's because this piece has a fault."

For the £100 BMW would charge, I can buy a new Antenna loop, pay for the CarSoft and possibly even an EWS module, if CarSoft will really do the realign. Already have a send/receive unit spare (thanks Ian) - I can read the OBD2 errors, sort any of those that are detailed.

If at that stage it doesn't work, I've got no choice but to buy another key and hope the bits I've swapped out have solved whatever has caused this on the last 2 keys... - The fact that the first time it ever did the intermittent non-start was when still in the complete donor car after the battery had been off for a month or so makes me wonder what that Live feed on the EWS is for.

Any further thoughts or ideas, folks?

[DanThe]

No, but that chinese carsoft wont realign shit, IMO of course

Code reading is the best place to start, for how easy it is I would change the EWS module and chip, see if it makes any difference

[Morat]

Key battery going flat?

I'll get my coat....

[Omi]

The chip inside the key is completely self-contained Morat matey...

The chip is about this big > |||||||| < and contains an induction loop, capacitor and Code EEPROM.

Inside, there's an induction loop which is tuned to a frequency of 125Khz. When the antenna ring on the ignition transmits that frequency this coil is excited and develops a tiny voltage which operates the code-chip and broadcasts the stored code back to the EWS unit... EWS module approves the key, connects the starter motor relay and sends an Individual Serial Number (ISN) code to the ECU.

When EWS sends that code to the ECU, the next rolling code is picked and broadcast back to the key transponder chip. Code is stored to the EEPROM ready to be broadcast on the next ignition attempt. - EWS Module has 10 slots for the last code on each of 10 keys... Hence when all these are used, you need a new module!

No battery! (If you were joking then I apologise for the patronising.)

[Morat]

No problem, interesting read! I only said it because I have an E46 and you have to alternate keys now and again because they charge from the vehicle when driving. E39 was the same. I knew I was guessing!

Good luck in finding the problem.

[DanThe]

The only reason those keys charge is to work the remote locking

[Speedtouch]

Why not just open up the EWS module and activate the relay with a simple switch circuit to avoid all the aggro?

[DanThe]

For the starter circuit yes, but not for the ECU start signal, I tested the signal given on my E34 and its a variable pulse, how that can be replicated I dont know. Even if you did replicate it you would only be able to use it with one ECU