1.4 BBY: random stall and buzzing noise

S

Sveshais

New Member
My 1.4 BBY A2 has developed an ill temper recently - it randomly stalls, won't start right away afterwards and there's a loud buzzing / humming noise coming from front left somewhere when ignition is turned on. Haven't really figured out a pattern when this happens, but I haven't observed it for a completely cold start, it usually happens after a short stop, like a quick grocery run.
I did manage to catch the noise on video, but couldn't pinpoint the source: https://drive.google.com/file/d/1jyWBFOdwhtG062XIE7A5C1U2DrX2F5D-/view
VCDS comes up with all these engine errors after that:

Code: 
7 Faults Found:
16786 - EGR System
            P0402 - 35-00 - Excessive Flow
16706 - Engine Speed Sensor (G28)
            P0322 - 35-10 - No Signal - Intermittent
17953 - Throttle Valve Controller
            P1545 - 35-10 - Malfunction - Intermittent
16955 - Brake Switch (F)
            P0571 - 35-10 - Implausible Signal - Intermittent
18057 - Powertrain Data Bus
            P1649 - 35-10 - Missing Message from ABS Controller - Intermittent
18058 - Powertrain Data Bus
            P1650 - 35-10 - Missing Message from Instrument Cluster - Intermittent
18043 - Powertrain Data Bus
            P1635 - 35-10 - Missing Message from A/C Controller - Intermittent
Readiness: 0010 0101

My initial suspect was a bad crankshaft pulse sensor and I had no means to have the car scanned back then, so I did change it a couple of months ago with this one: https://www.autodoc.co.uk/magneti-marelli/14925683 The problem actually went away for a while, or at least I though so, but it might have been just a coincidence and now it's back and more frequent than before. I'm puzzled about all the errors coming up altogether, any tips on what to go for next are greatly appreciated.
 
Sveshais said:
My 1.4 BBY A2 has developed an ill temper recently - it randomly stalls, won't start right away afterwards and there's a loud buzzing / humming noise coming from front left somewhere when ignition is turned on. Haven't really figured out a pattern when this happens, but I haven't observed it for a completely cold start, it usually happens after a short stop, like a quick grocery run.
I did manage to catch the noise on video, but couldn't pinpoint the source: https://drive.google.com/file/d/1jyWBFOdwhtG062XIE7A5C1U2DrX2F5D-/view
VCDS comes up with all these engine errors after that:

Code: 
7 Faults Found:
16786 - EGR System
            P0402 - 35-00 - Excessive Flow
16706 - Engine Speed Sensor (G28)
            P0322 - 35-10 - No Signal - Intermittent
17953 - Throttle Valve Controller
            P1545 - 35-10 - Malfunction - Intermittent
16955 - Brake Switch (F)
            P0571 - 35-10 - Implausible Signal - Intermittent
18057 - Powertrain Data Bus
            P1649 - 35-10 - Missing Message from ABS Controller - Intermittent
18058 - Powertrain Data Bus
            P1650 - 35-10 - Missing Message from Instrument Cluster - Intermittent
18043 - Powertrain Data Bus
            P1635 - 35-10 - Missing Message from A/C Controller - Intermittent
Readiness: 0010 0101

My initial suspect was a bad crankshaft pulse sensor and I had no means to have the car scanned back then, so I did change it a couple of months ago with this one: https://www.autodoc.co.uk/magneti-marelli/14925683 The problem actually went away for a while, or at least I though so, but it might have been just a coincidence and now it's back and more frequent than before. I'm puzzled about all the errors coming up altogether, any tips on what to go for next are greatly appreciated.
Click to expand...
Do all those DTCs come back, when cleared?
Mac.
 
Axit said:
Thats a lot of fault codes, how old is your battery, make sure its healthy.

John.
Click to expand...
Battery is a bit over 3 years old, was changed around November 2020. Before that it still had the original battery on it, so 3 year lifetime feels a bit on the low end, but I will check.
PlasticMac said:
Do all those DTCs come back, when cleared?
Mac.
Click to expand...
Yes, they do exactly that, I had all codes cleared for verification just before the stall happened again and all these came up, so I was wondering if there is something common that would trigger them.
 
Your battery should be OK considering it`s only 3 years old,

I would clean up the earth strap behind the passenger headlight, that is a common issue, if it`s not been checked.
 
3 years may well be the life of a budget battery or something could be killing it.

I would carefully check the battery terminals, auxiliary power box, earth to chassis from the battery and the starter earth strap that is also the earth for all engine electrical components. Looks tight is not good enough, they must be clean and have CONTINUITY.

Also have your alternator checked out as that may be the problem.
 
audifan said:
3 years may well be the life of a budget battery or something could be killing it.

I would carefully check the battery terminals, auxiliary power box, earth to chassis from the battery and the starter earth strap that is also the earth for all engine electrical components. Looks tight is not good enough, they must be clean and have CONTINUITY.

Also have your alternator checked out as that may be the problem.
Click to expand...
It's a Varta F19, I'd be quite surprised if it went out so early, but I did some measurements just in case. After sitting for a day and a half, it was 12.3V at rest and that's after all the experiments I had done above, so it had been drained a bit already, seems ok for the age.

I also cleaned the earth connections at the battery and behind the headlight, charged the battery fully and measured the voltage at battery terminals with engine running, headlights and AC on - it was 14.3 while idling cold and 13.9 when warmed up, so alternator seems to be alright.

I've yet to check the earth cable continuity though, but I'm curious on what the source of the noise in the video might be? When that comes on together with the ignition, it's a sign it won't start. Switching the ignition off, waiting a minute, and then back on a couple of times usually helps.
 
Sveshais said:
It's a Varta F19, I'd be quite surprised if it went out so early, but I did some measurements just in case. After sitting for a day and a half, it was 12.3V at rest and that's after all the experiments I had done above, so it had been drained a bit already, seems ok for the age.

I also cleaned the earth connections at the battery and behind the headlight, charged the battery fully and measured the voltage at battery terminals with engine running, headlights and AC on - it was 14.3 while idling cold and 13.9 when warmed up, so alternator seems to be alright.

I've yet to check the earth cable continuity though, but I'm curious on what the source of the noise in the video might be? When that comes on together with the ignition, it's a sign it won't start. Switching the ignition off, waiting a minute, and then back on a couple of times usually helps.
Click to expand...
The description points to a dodgy electric pump in the tank. Should be virtually silent, if working, noisy bearing on the blink, or the impeller slipping of the shaft maybe?
Straight forward to change, consider replacing the whole unit, swill pot etc, not just the pump. Have a listen under the rear seat. If opening the tank to get at it, be aware of the risk, petrol vapours are explosive, and will not support life. Plenty of natural ventilation and nothing electrical near by. Dissconect the battery well before you start.
Also, could be petrol pump relay, they buzz when failing.
Mac.
 
Yes your alternator may be charging but could be draining the battery when the engine is off due to internal issues. remeber the other ends of the cables need to be clean also.
This would not cause a buzzing noise but possibly stall the engine.
 
Sveshais said:
My 1.4 BBY A2 has developed an ill temper recently - it randomly stalls, won't start right away afterwards and there's a loud buzzing / humming noise coming from front left somewhere when ignition is turned on. Haven't really figured out a pattern when this happens, but I haven't observed it for a completely cold start, it usually happens after a short stop, like a quick grocery run.
I did manage to catch the noise on video, but couldn't pinpoint the source: https://drive.google.com/file/d/1jyWBFOdwhtG062XIE7A5C1U2DrX2F5D-/view
VCDS comes up with all these engine errors after that:

Code: 
7 Faults Found:
16786 - EGR System
            P0402 - 35-00 - Excessive Flow
16706 - Engine Speed Sensor (G28)
            P0322 - 35-10 - No Signal - Intermittent
17953 - Throttle Valve Controller
            P1545 - 35-10 - Malfunction - Intermittent
16955 - Brake Switch (F)
            P0571 - 35-10 - Implausible Signal - Intermittent
18057 - Powertrain Data Bus
            P1649 - 35-10 - Missing Message from ABS Controller - Intermittent
18058 - Powertrain Data Bus
            P1650 - 35-10 - Missing Message from Instrument Cluster - Intermittent
18043 - Powertrain Data Bus
            P1635 - 35-10 - Missing Message from A/C Controller - Intermittent
Readiness: 0010 0101

My initial suspect was a bad crankshaft pulse sensor and I had no means to have the car scanned back then, so I did change it a couple of months ago with this one: https://www.autodoc.co.uk/magneti-marelli/14925683 The problem actually went away for a while, or at least I though so, but it might have been just a coincidence and now it's back and more frequent than before. I'm puzzled about all the errors coming up altogether, any tips on what to go for next are greatly appreciated.
Click to expand...
Is the noise you've recorded, with the engine running, or is that "the noise" on it's own?
The fuel pump relay, is, I think, in the under floor compartment, the under the passenger's feet, so, on the left ...
Mac.
 
PlasticMac said:
The description points to a dodgy electric pump in the tank. Should be virtually silent, if working, noisy bearing on the blink, or the impeller slipping of the shaft maybe?
Straight forward to change, consider replacing the whole unit, swill pot etc, not just the pump. Have a listen under the rear seat. If opening the tank to get at it, be aware of the risk, petrol vapours are explosive, and will not support life. Plenty of natural ventilation and nothing electrical near by. Dissconect the battery well before you start.
Also, could be petrol pump relay, they buzz when failing.
Mac.
Click to expand...
Fuel pump had it's share of issues a time ago, but has already been replaced back in summer of 2022 and that's on the rear.
PlasticMac said:
Is the noise you've recorded, with the engine running, or is that "the noise" on it's own?
The fuel pump relay, is, I think, in the under floor compartment, the under the passenger's feet, so, on the left ...
Mac.
Click to expand...
That's with just the ignition on, engine is not running. It's a left-hand drive, so the fuses are in driver's floor compartment, but the sound seems to be coming from the engine bay somewhere just couldn't pinpoint where exactly, and as you can hear in the recording, it's very loud.

Unfortunately I didn't find time for doing more thurough checks today, will have to see if this happens again during the work week.
 
Maybe get a used fuel pump relay and swap it out. There's not much that is powered on, at the first turn of the ignition switch, even less that can make that level of noise.
Mac.
 
Is something caught in the fresh air intake and contacting the blower fan blades?
 
Is it something to do with the ABS controller? - I note that there is a message that communication has been lost to the ABS controller in the DTC list. It doesn't sound like the fuel pump noise we get on our AUA as you open the door and put key in ignition as that's a transient whirr and noticeably from the rear of the car - this sounds more like the grumble you get when ABS is triggered at low speed on an icy driveway and you're getting that kickback through the pedal while the brake pressure is being pulsed on the locking wheel. Plus the ABS equipment is right there next to the a/c pipework.

Shot in the dark - could it be something daft like the G62 sensor or an ABS sensor playing up (ie transient short to ground or similar) so that a whole bunch of ECUs stop communicating because CANBUS is getting messed up?

The other thing around there that makes a noise is the EGR although from memory that's more of a clicking when it's being activated (in a diagnostic) rather than a buzz.
 
Does sound like ABS controller when brake fluid is being purged using VCDS but a bit slower than normal.
 
Also, the power steering pump is underneath the ABS controller, so it could be that making the noise.

The noise is clearly linked, so identifying that could be quite helpful.

For all of those errors to appear, something quite major is happening, either a short to ground, as mentioned above, or power loss to the ECU. I’m fairly sure no matter what happens to its CANBUS, the ECU should keep running the engine.
The throttle controller is only powered/grounded by the ECU, so the ECU is what’s faulting.
 
a-zwo said:
Also, the power steering pump is underneath the ABS controller, so it could be that making the noise.

The noise is clearly linked, so identifying that could be quite helpful.

For all of those errors to appear, something quite major is happening, either a short to ground, as mentioned above, or power loss to the ECU. I’m fairly sure no matter what happens to its CANBUS, the ECU should keep running the engine.
The throttle controller is only powered/grounded by the ECU, so the ECU is what’s faulting.
Click to expand...
Don't think the power steering pump is energised until the engine starts.
Assuming the noise is electrically related the interference that is likely to be caused could upset the ECU, and trigger the DTCs.
Mac.
 
Yes that’s right, my thinking was that it could indicate an issue with the pump if it is running, or maybe help narrow the search for an earth issue :)
 
It's got to be said the mechanics stethoscope would be helpful here.

Do you have the alternative? A long screwdriver rested against the different suspect parts with the handle held to your ear?
 
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