Daewoo Lanos 1.6 ('98) ECM weirdness

id go for the crank sensor, vauxhall models have problems with the crank sensor wiring outer covering crumbling then exposing the wiring to the elements & shorting out.

Thanks reg - I'll get under it at the weekend and have a good look at the wiring to the sensor - I've got some some spare split-loom handy for extra protection if I find I have to make good.

I'm pretty tempted to make a ALDL-RS232 (5V to 12V-odd) level converter for my laptop and start hacking the ECM, see what else I can get out of it - fair few bits and bobs of info on the internet. I don't like opaque systems, especially on an older car where main-dealer visits are something I like to avoid...

Cheers

Tim

Hiya,

It happened again... Went down the road 15 miles to see me Dad. Stayed for an hour. No start... Got dragged back by the AA.

Very wet day - wonder if that has anything to do with it.

Next day (today), it started first time.

There is definately a pattern here...

So I dropped it in the Vauxhall garage. Unfortunately, the trick I used to read off the fault code (paperclip on pins A+B of the ALDL diag port) "apparantly" caused the ECM to lose it's error log.

Not seen that documented anywhere - but I can't disprove what they say...

So, they cleared the codes and said get it dragged in when it does it again...

I had a very good rummage around the engine tonight. I can just about see the crank sensor - looks OK as does the wiring (split loom is intact at least and it doesn't look like it's been touching the exhaust manifold and melted or anything like that).

Unfortunately, it's buried under (and above) so much crap that I can't even get my fingers on the wires to be sure... I can see the toothed wheel that drives the sensor though. Oh for a 2 1/4 Series III Landrover with a sit-in engine bay...

According to the workshop manual CD, there is also a camshaft sensor on the DOHC engine - couldn't find that though, despite taking the cylinder head cowling off.

This is not very good - weird-arsed intermittent fault...

I've check the ignition leads - they seem OK. Just had new plugs.

Any more inspirational ideas would be most welcome :)

Specifically - what sensors does it definately need to run? I'm aware that a number of sensors can fail but the ECM can cope in limp-home mode.

I'm guessing it wants the cam, crank and petrol pressure sensors at a minimum. I'm also guessing it can survive a Lambda/oxygen sensor failure and failure of any temperature sensors (air and water). Woudl I be guessing right?

What would happen if an injector solenoid when open circuit - would the ECM even notice?

Cheers and thanks for the advice,

Tim

When it refused to start did you also lose any ignition / warning lights on the dash? That happened to my Lanos and it was a lose connection. Remove the inside passenger kick panel and make sure all the connections & multiplugs are secure as these can come lose over time, especially with passenger traffic. You can see some of the connections through the fuse panel flap but remove the kick panel for better access. If you need to get at the crank sensor, if it's similar to the sohc you can get better access through the o/s wheel area.

No, all was well.

That's worth knowing.

That too. Thanks.

Having given up with Vauxhall, I had a word with the village mechanic. We are both of the opinion that it *might* be the crank sensor. It's a fairly cheap part (so he thinks) and he had a Vauxhall with a very similar problem last year where changing the sensor fixed it. So I've asked him to do a speculative replacement, where I accept responibility if it doesn't fix the problem.

Only panicing a bit because I've got some airport runs coming up and random failures aren't easy to tolerate right now :(

I can certainly go through the rest of the system and check connectors with the handy tips above.

Cheers

Tim

I see why now. I've never paid attention to the secondary fuse panel in the P/S footwell -but I notice that it supplies bits of the ECM and various engine sensors. That figures...

Haven't had the trim off yet (it's dark) but I do note some of the connectors you mentioned. Will investigate further.

Cheers

Tim

When I bought my lanos the fuel gauge didn't work. I changed the fuel pump/sender inside the tank and also popped in a complete instrument panel from a breakers but still the gauge didn't work. Then one day I parked the car and it refused to re-start. I checked both fuse boxes and it was just by chance when looking through the inside fuse panel with a torch that I noticed one of the multiplug connectors (the big long one) didn't look properly pushed in. I removed the kick panel and saw the plug was askew so I pushed it in and not only did the car start first time but my fuel gauge has worked ever since.

Another thing that's comes to mind is the immobiliser. When the car fails to start did you notice if the led next to the clock stops flashing when the ignition is on?

Ah, excellently specific things to look for - cheers.

Good point. Same thought occurred to me, too late to look out for it until next time... I don't remember it flashing but I can't be sure because I wasn't really looking at it...

I've been kind of distracted by the Code 19 I got the ECM to flash out on the check light when I bridged Pins A+B on the ALDL port... That says crank sensor (or fuel pressure sometimes, according to various websites) but I don't know for sure if it's a red herring...

Cheers

Tim

Hi

Just a follow up with new information (partly for the benefit of Google)...

The wife made 4 short journeys today (1/2 mile each - happens with kids and rain), then a 5th 3 mile journey to give me a lift back from the station. Boink - refused to restart in the station carpark.

So, following on from the good Mr redwood's excellent advice, I tried everything:

1) Immobilser LED goes off when turning ignition on - also used both our keys in case of dicky tansponder chips, so not immobiliser failure (AFAIK).

2) Lights OK on dash - AIRBAG and ABS (on, off in usual sequence), battery charging, oil, brake all on.

3) I managed to prise the passenger footwell fuse cover trim off and I found all the connectors mentioned perviously. All sound. I pulled as many off as I could and replaced them, then removed and replaced every fuse there and in the main fusebox in the engine bay that vaguely related to engine functions. Checked the wiring loom from the pass FW for a foot or so under the carpet - doesn't seem damaged.

Had a chat with the AA bloke as the corpse was being dragged back. He agreed too that the crank sensor was not unlikely, so that's booked for swapout with the village mechanic for Tuesday. I'll ask him to thoroughly examine the wiring to it whilst he's got access.

3 hours later, still dead. I'm certain it will recover tomorrow morning (although it probably won;t now I've gone and said that!)

I reckon it must be something to do with the sensor getting hot (or wiring - that's not fully ruled out yet) and *perhaps* the sensor cannot produce a good enough signal whilst cranking. Possibly the supply voltage is too low whilst the starter is drawing and it's throwing it over the edge. That would be a neat explanation of why it never cuts out while running (yet). Or the fact that the engine cranking speed is low compared to idling speed - as it's a magnetic pickup, speed may affect impulse levels (assuming it's a coil rather than a Hall-effect sensor).

Don't believe I have a camshaft sensor (can't find it if I do) so it's really got to be the crank.

Hopefully, if it gets replaced on Tuesday, I'll know for sure in about 3 weeks if it doesn't fail again.

I'll be sure to report back when I have anymore information...

Cheers

Tim

Oh yes - can't remember if I said this already...

Last week when it died, I drove it the next morning down to Vauxhall who plugged their diag unit in.

They said there were no codes other than "battery terminals shorted" (exact words varied everytime he mentioned it).

They then blamed me for shorting pins A+B and said that cleared the computer's log. Then went on to say if it did it again, I shouldn't attempt to start it (that might clear the log) - just get it towed and dumped outside their place (in the middle of a slightly pikey industrial estate on a load of double yellow lines at night - yeah, right...)

Mentioned this to the AA bloke tonight and he was of the opinion that Vauxhall were possibly talking b***ocks. The AA recovery vehicles carry an OBD-II (modern current) diag unit. For older units like mine, they themselves use the short-two-pins-on-the-port trick to flash the code out via the dash engine-check light. It is apparently a kosher thing to do...

At least Vauxhall didn't charge me anything.

Top marks to the AA bloke who turned up in 20 minutes flat, and to the phone operator who listened to my pleas to send the truck straight away rather than a bloke in a van... 2 recoveries in a fortnight - I'll be blacklisted soon ;-o

Cheers

Tim

And another tiny followup...

Exactly 4 hours are bolloxing itself, it starts first time.

Got to be heat related methinks...

Cheers

Tim

Yes, from the sounds of it it does appear to be a heat related problem. Sorry I can't be of any more help but do let us know if you discover the problem as it will be worth knowing for future reference.

The only known ECU problem that I am aware of is the high idle problem that is a common fault with the Lanos. At some point the engine will not idle at the correct 850rpm but instead idles at around 1500rpm. Daewoo are aware of the problem and have a software update for the ecu. To save paying Daewoo I found this temporary fix that's worth knowing.

Ignition On Disconnect Idle Speed Control Valve Ignition Off Re-connect Idle Speed Control valve Repeat 4 or 5 times Start Vehicle - It may not idle unassisted so use the throttle. Keep vehicle idling on throttle to initialise self learn process It should now idle within parameters.

That fix should last a few months, just repeat if the problem reoccurs.

No, not at all - you've been a great help :)

Thanks to your advice I've checked all the silly things it might have been, which means I'm less worried about putting 100 quid or so on the line for a speculative change of the crank sensor...

And you've formed part of a consensus decision, along with me and two recovery men. Our village mechanic hasn't got any more idea than Vauxhall why it's gone wrong, but he agrees it's likely too, and I'm happy enough not to blame him if I'm wrong, and he's happy (unlike Vauxhall) to "have a go".

That's interesting. Never had the problem, but the workshop manual does detail a procedure you should follow if the battery is ever disconnected, which goes like this (quote verbatim):

"IDLE LEARN PROCEDURE Whenever the battery cables, the powertrain control module (PCM)/engine control module (ECM), or the fuse is disconnected or replaced, the following idle learn procedure must be performed:

1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is above 185³F (85³C).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic transaxle, apply the parking brake. While pressing the brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is complete."

Mind you, the workshop manual thinks I have a 16pin OBD-II diag port and a few other bits I don't have, so the above might not apply to my earlier ('98) engine. There seemed to be a few minor changes on the Lanos' around

2000. Wonder why Haynes never did a Daewoo manual set.

Cheers

Tim

Hi y'all,

Righty ho. Village bloke changed the crank sensor today. Noticed something that I hadn't before:

The car drives so smoothly now. It was getting a bit jumpy before (mechanic thought it was rough too). I'd got used to it - and just put it down to age.

49+VAT for the part and 30 quid to fit.

So, the sensor was definitely ill - hope that was also the root cause of the starting problems.

I'll give it a couple of weeks of thrashing about and report back, hopefully to close this thread with a result...

Now, where are those chicken bones...

A big thanks again to everyone who gave ideas and useful tips :)

Cheers

Tim

On an aside, when the mechanic took the car in to the garage he works at part time, a Vauxhall was in with dicky-engine problems. That turned out to be the throttle flap sensor.

Glad you got it sorted and hope it stays that way. I'll remember that one for the future if similar happens to my Lanos.

The other thing to watch out for, according to the local mechanic, is the throttle position sensor. While he was in the workshop doing mine, a Vauxhall of some sort. with a not dissimilar engine, was being worked on in the next bay and was experiencing all sorts of lumpiness, even at idle. New throttle sender (even just plugged in, not mechanically connected) settled it down straight away apparently.

I've thrashed the nuts of mine and it hasn't broken yet.

Heathrow run on Wednesday should be the final proof :)

Cheers

Tim