Mondeo MKIV - electrical issue

[Andy 308GTB]

2011 Ford Mondeo MKIV.

The following electrical faults have all appeared at around the same time after 12 years of trouble free motoring...

1. The Car Alarm has started to go off occassionally and without cause
2. The 'Bonnet Open' warning appears on the dash every 2 or 3 times the car is started. The bonnet isn't open.
3. The proximity sensors are not working. Although the car now emits a continuous tone for several seconds when reverse is engaged.

Is the first step to disconnect the battery for a few minutes and see if that resets the ECU? Any other ideas or experience?

Thanks

[Novexx]

Sounds like a BCM (Body Control Module) issue which is often caused by water ingress into the module or connectors.

The BCM is / or is above the fuse box (cant remember if it's the same unit or not), tell tale signs are corrosion in the connector block or on solder joints. Stripping & cleaning the conectors & cleaning solder down with contact cleaner may resolve the issue, otherwise a new / refurb BCM may be required (will need coded or cloned).

[Andy 308GTB]

Novexx said:

Sounds like a BCM (Body Control Module) issue which is often caused by water ingress into the module or connectors.

The BCM is / or is above the fuse box (cant remember if it's the same unit or not), tell tale signs are corrosion in the connector block or on solder joints. Stripping & cleaning the conectors & cleaning solder down with contact cleaner may resolve the issue, otherwise a new / refurb BCM may be required (will need coded or cloned).

That's a good answer, the 'Bonnet Open' warning first occurred after I had washed the car. My Saturday morning is now taken care of.

[Polly Grigora]

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

[E-bmw]

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

[Andy 308GTB]

E-bmw said:

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

When the bonnet latch were first triggered the alert, I got a new one from eBay (£10 !). This turned up yesterday, so I will fit that today.

[Polly Grigora]

E-bmw said:

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

Hadn't considered washing the car would alter the bonnet switch mounting position, good thinking on your part

[E-bmw]

Polly Grigora said:

E-bmw said:

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

Hadn't considered washing the car would alter the bonnet switch mounting position, good thinking on your part

If it is right "on a knife edge" of adjustment it doesn't take much.

My V40 was a bugger for exactly this until I adjusted it a bit, although mine was showing bonnet open when driving, even though closed.

[Andy 308GTB]

E-bmw said:

Polly Grigora said:

E-bmw said:

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

Hadn't considered washing the car would alter the bonnet switch mounting position, good thinking on your part

If it is right "on a knife edge" of adjustment it doesn't take much.

My V40 was a bugger for exactly this until I adjusted it a bit, although mine was showing bonnet open when driving, even though closed.

My £10 eBay replacement bonnet latch appears to have cured problems #1 & #2. Thanks all.

Problem #3 (parking sensor emits a continuous tone when reverse is engaged) apparently indicates that one sensor has failed. With the right diagnostic tool it is possible to identify which one. Needless to say I will be receiving one new sensor (eBay £16) and taking a more trial & error approach.

[E-bmw]

Andy 308GTB said:

E-bmw said:

Polly Grigora said:

E-bmw said:

Polly Grigora said:

Water in the bonnet switch or its plug will give a bonnet open warning on the dash and also trigger the alarm

As will a bonnet latch that needs a slight adjustment.

Either way, the bonnet switch will also likely be an alarm input & cause both your first and second issue

Hadn't considered washing the car would alter the bonnet switch mounting position, good thinking on your part

If it is right "on a knife edge" of adjustment it doesn't take much.

My V40 was a bugger for exactly this until I adjusted it a bit, although mine was showing bonnet open when driving, even though closed.

My £10 eBay replacement bonnet latch appears to have cured problems #1 & #2. Thanks all.

Problem #3 (parking sensor emits a continuous tone when reverse is engaged) apparently indicates that one sensor has failed. With the right diagnostic tool it is possible to identify which one. Needless to say I will be receiving one new sensor (eBay £16) and taking a more trial & error approach.

Good to hear.

Yes, a solid beep indicates duff sensor, and I am sure a 1/2 decent code reader will tell you which it is, if you don't have one, post up where you are, someone may be near enough to have a go.

FWIW some cars REALLY don't like el-cheapo chinese copy reversing sensors, but it is worth a go.