Citroen XM Forum

...yes, I will do that with all the relays and contacts, I will have to check everything.

...I noticed that this part leaks oil, what is that part for, I assume it's some kind of vacuum.

..is there a sealing O ring or a gasket?

That is the vacuum pump, which uses O rings as a seal, but that oil looks like it is coming from either the breather pipe connection, or the cam cover seal.
O rings, 4556 07 (3 off, 5.5x1.5mm), 4556 07 (1 off, 44x2mm)

The cam box seals do tend to leak as they age and really make a mess of the back of the engine. Fit a new one, P.n 0249 70.
Use a decent brand, otherwise they tend to not fit properly: Corteco, Victor Reinz, Payen, Elring, FIA.

Gasa wrote: Wed Dec 28, 2022 10:25 am ..thanks for the explanation, I'll look into what the problem is, the battery warning light didn't light up before, I mentioned that after some time you could hear a relay tripping and the light went off immediately, it means that some relay is not responding well or there is a problem in the alternator regulator.

The only relay I can think that feeds power for 10s is the interior lights short timer, though that shouldn't feed power to the battery lamp.
Logic says that if this fault only occurred after reconditioning the alternator, it is linked to that.
Use an independent power source and test lamp to excite the alternator and see if that takes the 10s to shut off after the engine stops. If it is definitely the regulator holding the batt lamp on and it has no current draw after 10s, then it probably not worth bothering about.

...I did a small test with this cable, when I disconnect it, the battery indicator does not light up.
it seems that the regulator may be broken, I noticed that the lights vary, the lights are a little brighter and then a little weaker, there are oscillations.


...today I looked a bit around the ABS, I measured the voltage, it has 2.30 V, is it weak or should it be 12V ,so the ABS unit has voltage, I will look at the rear wheels these days to see if it has the same voltage.

I still don't know which ABS system is on it, I took a picture of the connector and it says ATE.

Gasa wrote: Thu Dec 29, 2022 12:30 pm ...I did a small test with this cable, when I disconnect it, the battery indicator does not light up.

it seems that the regulator may be broken, I noticed that the lights vary, the lights are a little brighter and then a little weaker, there are oscillations.

Sounds possible, but where is the +12v feed for the lamp coming from?

Gasa wrote: Thu Dec 29, 2022 12:30 pm ...today I looked a bit around the ABS, I measured the voltage, it has 2.30 V, is it weak or should it be 12V ,so the ABS unit has voltage, I will look at the rear wheels these days to see if it has the same voltage.

Measured where?
The system runs on +12v.

Gasa wrote: Thu Dec 29, 2022 12:30 pm I still don't know which ABS system is on it, I took a picture of the connector and it says ATE.

Ate, Teves Mk4.

Have you run the diagnostic blink codes, if not start there.

As a matter of interest, what was the sensor resistance? It should be ~2,200 Ohm.
The sensors are simple Hall Effect devices, which generate a small AC voltage when the wheel rotates, so can be tested with a voltmeter, or scope.

I measured the voltage at the ABS sensor connectors.I will check all the sensors tomorrow, I haven't done anything with reading the codes.

...you were right, the gasket on the valve cover is leaking oil, tomorrow I will replace that gasket.

I've never checked, but 2.3v sounds like a reasonable bias voltage for the sensors to run on. The sensor will then create an AC voltage to run on top of the 2.3v DC, so likely readings are probably 2.3vdc +/- 2v.

...I measured the sensors again today, I only measured the front ones, the right sensor is broken, it doesn't show any resistance.
I didn't measure the rear sensors, they must be inaccessible by a crane or a channel to get to the contact, I will do that another time.

...right sensor
...left sensor
..voltage is the same on both sides.

Gasa wrote: Sat Dec 31, 2022 4:21 pm ...I measured the sensors again today, I only measured the front ones, the right sensor is broken, it doesn't show any resistance.


...right sensor

IMG_20221231_145459.jpg

I think you mean it showed open circuit, no resistance would show 0 ohms. Your meter is showing Over range...in Meg-ohms, in other words, no connection.

You can meter the sensors from the Ecu connector.
Interestingly, your car appears to have 1,100 Ohm sensors fitted. I thought all the Teves sensors were 2,200 Ohm, earlier Bendix sensors are 1,100 Ohm.
Within a reasonable range, the Ecu isn't interested in the resistance of the sensor, just the voltage pulses the sensor feeds back to the Ecu.
Both 1,100 Ohm and 2,200 Ohm sensors can be installed on the Bendix system, so it stands to reason that the same is true for Teves Mk4 system.

I suspect if you re-install the dashboard lamp, fit a new sensor, you will have working Abs. It's possible there is just a poor connection to a sensor, the connector, or lead can suffer.

Have you read the fault codes?