Still not worked it out yet. But I've found ways of reducing the occurence rate of transient ECU crises by keeping the battery charge high.
I should explain - it's my partner's car. Consequently when it causes her a problem it causes me anywhere between 2x problem and 4x problem in algebraic terms. I like to keep my problem levels low, and right now the easiest and most effective way of keeping this problem away particularly during winter is to keep the battery charged every 2-3 days with the CTEK (which plugs into the same extension as the 60W incandescent bulb I clip onto the cupholder to keep the cabin defrosted overnight).
So the current hypothesis is 205,000 mile alternator (or its regulator) not being 100% healthy, even though the battery is itself fine. The secondary hypothesis relates to my experience driving it after toys have left the pram and my own car has been repossessed by my partner for however long she wants, which is that when the weather is cold I would often make it halfway to work, and then while approaching one particular junction, on pressing the brake pedal and beginning to steer, the warning sound and lights all happen together. Park up, switch off, switch on, reset / warning lights off, carry on to work. But this could still be down to voltage drop. Hence intention to fit a refurbished 110A alternator / new belt / tensioner and see if this solves the issue.
I should explain - it's my partner's car. Consequently when it causes her a problem it causes me anywhere between 2x problem and 4x problem in algebraic terms. I like to keep my problem levels low, and right now the easiest and most effective way of keeping this problem away particularly during winter is to keep the battery charged every 2-3 days with the CTEK (which plugs into the same extension as the 60W incandescent bulb I clip onto the cupholder to keep the cabin defrosted overnight).
So the current hypothesis is 205,000 mile alternator (or its regulator) not being 100% healthy, even though the battery is itself fine. The secondary hypothesis relates to my experience driving it after toys have left the pram and my own car has been repossessed by my partner for however long she wants, which is that when the weather is cold I would often make it halfway to work, and then while approaching one particular junction, on pressing the brake pedal and beginning to steer, the warning sound and lights all happen together. Park up, switch off, switch on, reset / warning lights off, carry on to work. But this could still be down to voltage drop. Hence intention to fit a refurbished 110A alternator / new belt / tensioner and see if this solves the issue.