Xantia – Voltages reading

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lancia58
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Xantia – Voltages reading

Post by lancia58 »

Using the Lexia I got the following readings for the voltages

1) When reading the engine ECU the voltage will read 12v
2) When reading the AL4 ECU the voltage will read 14.5 V

Voltage of 14.5 v is normal and using a voltmeter this is what is measured on the battery terminals . Does the above indicate that the engine ECU voltage it too low ? If yes will it affect its functionality , mainly the analog to digital conversion of the various sensors ? Is there a wiring scheme that I can use to track the ECU voltage feeding and find why it drops to 12V ?

Thanks
Zohar
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Re: Xantia – Voltages reading

Post by Peter.N. »

I would suspect it has a voltage regulator in circuit, try it without the engine running and see if its still 12v

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lancia58
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Re: Xantia – Voltages reading

Post by lancia58 »

The voltages changes as the revs change so I guess there isn't a voltage regulator

Thanks
Zohar
Xantia 2.0 16V Automatic make year 2000 LHD
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Re: Xantia – Voltages reading

Post by myglaren »

More likely the regulator has failed.
lancia58
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Re: Xantia – Voltages reading

Post by lancia58 »

Is this regulator part of the engine ECU ? But if it fail how comes that the ECU still functions ?

Thanks
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
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myglaren
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Previously:
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R4, R11TXE, R14, R30TX
x 4888

Re: Xantia – Voltages reading

Post by myglaren »

Can't answer that Zohar but if the ECU doesn't carry it's own internal regulator I imagine it will fail sooner or later if presented with varying voltages especially over 12V.
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