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rma

ECU Issue (Temp Max, Traction Light on, No start)

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Hello,

 

I have a 2002 330ci Sport Coupe with a suspected ECU issue.

 

Symptoms:

- No start, cranks but no firing

- Temp Gauge Max, car hasn't been driven in 2 days. Will go straight to max shortly after key is in position 2

- Traction Control light permanently on

- Can't get any information from the OBD menu

- INPA keeps saying "Error 19"

- No fuel pump noise (car has 3/4 tank of fuel). Fuel filter changed in 2014, 20k miles since it's been changed.

 

The car has been running fine up until 2 days ago. I went down to BMW to get a bolt for the alternator terminal, as I stupidly didn't put mine back on after a oil filter housing gasket change. The car has no under tray and it was raining heavily when I drove down there and back. I attached the bolt down there and the alt reads 13.5V when driving, so it's charging the batt.

When I got home (15 mi drive) I turned the car off, and came back to it earlier this evening. The lights I describe are lit up, and it just cranks with no firing, I let it crank for 1/2 secs as I assumed it wouldn't start due to it's weird behavior.

 

I have:

- Checked all fuses in fuse box (Including the large 50A fuses x2), as well as in the "MOTOR-SICHERUNGEN" Box under bonnet.

- Battery reads 12.4V with multimeter and OBD.

- Tested for shorts by setting multimeter to DC V, disconnecting the negative terminal, connecting the red on multimeter to battery negative, and connecting the negative lead on the MM to the ground bolt in boot.

- Left the battery negative terminal disconnected for a few hours to reset ECU.

 

I'm either suspecting the ground strap on the underside of the car, or relays have been fried. Seems a bit strange this happens after I get my alternator properly charging the car.

 

Any ideas? My experience with this car so far has been nothing but a pain. Admittedly I shouldn't be running it in bad rain with no undertray, so I guess this is the second thing that's gone wrong because of me :mad:

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I doubt the lack of undertray is your cause of the problem. Did you drive to the dealer with the alternator disconnected? Not that that is necessarily an issue, especially if it's not that far.

The fact that you can't communicate with the ECU would be my starting point. Are you sure it's not anything with the laptop and/or cable? That's where I would start.

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2 hours ago, 2clubsp said:

I doubt the lack of undertray is your cause of the problem. Did you drive to the dealer with the alternator disconnected? Not that that is necessarily an issue, especially if it's not that far.

The fact that you can't communicate with the ECU would be my starting point. Are you sure it's not anything with the laptop and/or cable? That's where I would start.

 

I drove down to the dealer with the alternator connected, but it was only putting out 11.5v - not enough to charge my battery which explains the discharge issue. As soon as I put the nut to secure the positive lead onto the back, I get 13.5v ish depending what's turned on in the cabin. The batt reads 12.3/4V when everythings been off for a few hours, so I can confirm the battery is good and the alternator is working fine.

The dealer is about 20 mile round trip mostly dual carriageway - I charged the battery before leaving as I don't want to do lasting damage to a 2 month old battery, and I've also heard charging a low battery via the alternator can damage it, just in case I got the problem solved which I did.

 

The laptop is fine as I can detect the ignition on and cable connected, just can't read anything from the ECU. I get a load of error 19's from INPA.

 

Last night I took the battery off and the MOTOR-SICHERUNGEN box to take it indoors to get inside of it. I just went out to the car, put the fuses back in and the battery. The EML light flashes when the key is in position 2, but the temp gauge stays normal. Traction light stays on, and the handbrake light is yellow when disengaged. Still no start. No OBD2 functions apart from battery/cluster test work.

When the key is in position 2, here is what I see: I did disconnect the rear cluster in the boot, so that is normal

IMG_0675.thumb.JPG.6b1fba52148e3eff34640d2e9f4859be.JPG

 

My concern with no undertray is the ground strap underneath the car. This has only happened since I've driven in the rain, and they appear to be much more sensitive electronically.

 

When the rain stops, my plan of action is to:

 

- Check the ground strap, disconnect and clean just to rule it out. I will also do this for the ground in the boot, and the ground by the fuse box.

- Connect my laptop to the OBD2 port, I doubt it will work but might as well rule it out

- Use my multimeter to test the relays for resistance (continuity?). I cannot hear the fuel pump when I turn the car on, but the car knows when the MOTOR-SICHERUNGEN box is disconnected.

 

Is there a better name for the MOTOR-SICHERUNGEN box? Bit of a mouthful.

 

Cheers

Edited by rma
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I can connect to the car via INPA now, there was 15 errors so I saved them, then cleared them, and now there's 3 stored which are:

 

1. 69 Kraftstoffpumpenrelais  (Fuel Pump Relay)

2. 36 Hauptrelais (Main Relay)

3. 74 Relais Klimakompressor (Air Conditioning Compressor Relay)

 

The 15 errors which were stored before I cleared them are:

1. 11 Kuehlerausgangstemperatur ( Engine coolant temperature sensor in radiator outlet high/low )

2. 242 Verbrennungsaussetzer Zylinder 5 (Misfire)

3. 239 Verbrennungsaussetzer Zylinder 2 (Misfire)

4. 241 Verbrennungsaussetzer Zylinder 4 (Misfire)

5. 228 Lambdareglerabweichung Bank 2 (Lambda Deviation Bank 2)

6. 243 Verbrennungsaussetzer Zylinder 6 (Misfire)

7. 53 LLFS oeffnende Spule elektrisch (LLFS opening coil electric)

8. 27 LLFS schliessende Spule elektrisch (LLFS closing coil electric)

9. 100 Steuergeraetefehler (Control device error) ?????

10. 37 Schaltverzoegerung Hauptrelais (Shift delay main relay)

11. 36 Hauptrelais (Main Relay)

12. 69 Kraftstoffpumpenrelais (Fuel Pump Relay)

13. 74 Relais Klimakompressor (Air Conditioning Relay)

14. 124 Variable Sauganlage (Variable intake system) Disa?

15. 123 Thermostatheizung, KFK (Thermostat heating, KFK)

 

So it appears I've blown the Fuel Pump Relay and Main Relay (Blue DME Relay?). My understanding is the fuses would blow before the relays sustained any damage.

When driving I didn't suffer any misfires, or rough driving either.

 

What concerns me the most is my initial inability to communicate with the DME. Would a bad ground strap underneath cause this issue?

 

And I have an ohms testing section on my multimeter so I'll go and test my relays now - I'm going to assume theyre dead, will rule it out anyway.

 

Why has this happened initially? I wouldn't have thought running with no undertray would cause this in the wet... I guess I'll be leaving it on but would like to get to the bottom of this

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Okay so I've just pulled the DME (Light Blue) relay and tested it.

 

I get 95 Ohms resistance between pins 30/85 and 3 ohms between 87 and 87.

 

Seems normal to me, if I try and connect pins 30 and 87 or 85 and 87 I get no connection, so it appears to be functioning okay.

 

Realised the DME relay isn't the main relay, as the main has 5 pins instead of 4.

 

All of the pins have below 100 ohms, and 98 has nothing as I assume the relay has to open for that to have any current.

 

 

Apart from grounding I don't understand what else could be the issue

Edited by rma
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That's a LOT of unrelated errors, maybe as you say due to a sporadic ground fault. There is no way that all of those individual items will have failed. It'll be symptomatic of a power or grounding issue. That's my guess anyway.

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2 hours ago, 2clubsp said:

That's a LOT of unrelated errors, maybe as you say due to a sporadic ground fault. There is no way that all of those individual items will have failed. It'll be symptomatic of a power or grounding issue. That's my guess anyway.

 

Just checked the ground by the battery, the ground strap underneath the car, the ground by the fuse box, ground by brake booster and the ground either end of the cylinders. All show 2-3 ohms of resistance and no live current.

 

 

This car is starting to test my patience, I've had less than 150 miles of trouble free motoring in 2 months :mad:

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18 minutes ago, 2clubsp said:

2 to 3 ohms would be terrible. It should be 0.3 ohms or thereabouts. It is hard to measure though, so maybe a limitation of your meter.

Have you looked for water or corrosion at the ECU connector?

My meter is a cheapy from Amazon, was about £25 I believe. That whole box is dry, everything in that box is clean too. Disconnected the leads and it all looks spotless.

 

 

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Made some progress.

 

Tested and cleaned all grounds with no issue, seems to be intermittent so I started disconnecting non essential things to narrow down the problem.

 

Appears to be the vanos inlet solenoid, the error I get in INPA is:

 

- 21 VANOS-Magnetventil Einlass-NW | translates to: "VANOS Solenoid Valve Inlet NW"

 

When this is disconnected, the fuel pump primes and this is the only error on the OBD. When I reconnect it, the EML light flashes, check engine stays on and the OBD has loads of errors with failed relays...etc.

 

There does appear to be an oil leak from the valve cover gasket which trickles down onto the sensor - it was changed in 2014 but perhaps a CCV change (OEM) has provoked this issue. I was planning a vanos refresh later in the year so it will all be redone anyway.

 

If you ever have any electrical issues, check the fuses work, test relays with a multimeter then start disconnecting things to find the culprit.

 

I'll clean it up and see if it wants to work, if not I'll have to call around and see how much this costs.

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4 hours ago, 2clubsp said:

Glad to hear you seem to be making some headway. That's some weird s**t you got going on. Hope you get it all sorted.

 

Yeah no idea how this has happened. I always dread electrical issues for this very reason.

 

Turns out I need a new Camshaft Sensor, at the side of the engine underneath the CCV tube.

 

Any idea who makes the OEM sensors? All I see on ECP is HAAS and Delphi, the Delphi being £20 more. Rather get the proper sensor than some cheapy

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