Suspect Alternater

[msg1]

Hi All

I have a 2009 Avensis T4 estate 2.0 L .

The Battery light is on and I have measured the volts on the Battery at idle and then again when at around 2000 rpm . No difference to the voltage sitting at around 12.8v.

So I have kept it charged overnight, every night and the car has been running for a couple of days with no problem. (its booked to be repaired on Friday)

I got a bit lazy over the weekend and didn't charge it for 2 nights. Used it last night and so lights etc were being used and no surprise, other warning lights started to show up , the first being the power steering warn and then a couple more warning lights and then no steering as the pump stopped etc. Luckily I was 500m from home and so was able to steer the car without assistance at  5 mph.

My thoughts are that the alternator it not outputting anything and so was wondering before I get a new one, if the diode block is serviceable on these alternators?

I suspect that I would at least get some output from the alternator if it was just loosing its efficiency due to windings failing etc , Its this that has made me think that it could be the diode/ regulator block.

Any thoughts and help would be greatly appreciated.

Lesson learnt , If anyone sees the Battery light on , be warned as the steering pump must be electric as this failed very quickly after the steering pump warn light came on (could have been nasty at speed)

 

[mrfixer]

If the regulator is faulty the output is often just low. If the diode pack is faulty the output will show a lot of ripple (check with a 'scope). Generally they make a whining noise too, when a diode is bad.

You can get parts from the rotating electric suppliers like H. Bowers or Butts. If the unit has done a lot of miles then an exchange unit might be best.

I believe your car has column-mounted electric power steering. If the Battery or alternator is not in tip top condition it will malfunction.

[msg1]

Hi Jim

Thankyou for your quick response.

I will look on a scope tonight and see what I can find.

The car has clocked 65000 miles, so not too bad. 

Noted the comment about the Battery and alternator being in tip top condition!

Thanks again

Will let you know how I get on

Regards

Mark

[mrfixer]

23 minutes ago, msg1 said:

Hi Jim

Thankyou for your quick response.

I will look on a scope tonight and see what I can find.

The car has clocked 65000 miles, so not too bad. 

Noted the comment about the battery and alternator being in tip top condition!

Thanks again

Will let you know how I get on

Regards

Mark

Obviously its a three phase output which is rectified, so if a diode goes bad you get an output waveform with a dip on about a 70:30 mark-space ratio.

Diode packs are about £30 and regulators about £25. A warranted rebuilt unit is about £120. You can get brand new Chinese made units for under £100, no idea how good they are but plenty get sold..

[msg1]

Hi Jim

So it got to the point where I had to get it repaired by a third party!

A specialist serviced the unit replacing the diode pack and the regulator unit.

All working except the Battery light is now dimly lit when ignition is on!

Took it back to be told "I cant find anything wrong its just one of those things"

So whilst its got me out of an immediate problem I now still need to look at it myself to see why the light it dimly lit.

Whats worrying is that when i turn the ignition on I don't get the full brightness light as usual. But the guy did say it came on using he's diagnostics

so at least I will know if its not charging before its too late !

It is a painful push button start , so maybe they behave differently , but I cant thing how or why.

I suspect that one of the diodes is faulty

I know what I will be doing this back holiday.

Thanks again for your help

Mark

 

 

[mrfixer]

The charge warning lamp lights up whenever there is a difference in voltage between the + output terminal on the alternator and the positive terminal on the Battery..

It could indicate poor wiring, worn brushes, a faulty diode or a faulty regulator.

Make sure that the cable connected to + on the alternator is clean and secure.

Make sure that the cable running from alternator + to Battery warning light and further to positive terminal on the Battery is free from defects.

Measure the voltage on the battery with the engine off and everything electrical switched off.

Measure the voltage on the battery with the engine running at 1500rpm.

Connect a jump lead from alternator body to battery neg. If the light goes out you have a poor earth somewhere. VERY CAREFULLY connect a jump lead from alternator + to battery +.  If the light goes out you have a fault in the positive feed circuit.