S60 auto erratic speedo and tachometer issues

[ALBERT10]

S60 T5 AUTO 2001

Sometimes the speedo does not display the correct speed and appears to stick and jump. Same with tachometer, can jump about and auto box change seems not right.


Always when starting the car it won't change up properly from low speeds, just keeps increasing revs. I have to take foot off accelerator let revs completely drop, then needle bounces slightly then car will change up and behave normally. Then even if car is warm if switch off engine to get petrol the same change up problem occurs.

What could all this be?

[reggit]

The sticking clocks is the DIM failing, mine went in the same way. Fairly cheap to get repaired by a chap on here. Look on traders sticky threads.
Dunno if this will affect auto box though - mines manual.

[ALBERT10]

Originally Posted by reggit

The sticking clocks is the DIM failing, mine went in the same way. Fairly cheap to get repaired by a chap on here. Look on traders sticky threads.
Dunno if this will affect auto box though - mines manual.

Was yours jumping speeds? Mine can stick on 20 and then jump to 40. Can you still drive okay apart form incorrect speed showing? There are speedo apps you can use on phone if necessary or sat navs usually show speed.

[davebb]

Hi get your alternator checked as it may be on the way out and putting some ac in to the power system, this needs to be done with a oscilloscope,
Dave

[ALBERT10]

Originally Posted by davebb

Hi get your alternator checked as it may be on the way out and putting some ac in to the power system, this needs to be done with a oscilloscope,
Dave

Putting AC into the power system, can you explain this? I do have a gadget in cig lighter that shows the charging voltage.

The alternator was replaced a couple of months ago. The el power service light came on once since but not again.

The old one regulator failed and was charging high voltage before failing completely.

So maybe it could be something to do with alternator unit or installation? As probably a refurbished unit rather than brand new.

[davebb]

Hi if the diodes are leaky this will put ripple in to ecu, clocks,
do you know anyone with a into electronics with a scope, you need to set the scope on ac coupling, so it only reads ac, and read the voltage in mV,
LOOK ON YOUTUBE
https://www.youtube.com/watch?v=MGaHaIXZioA
you can not go by the charge light
Dave

[davebb]

Originally Posted by ALBERT10

Putting AC into the power system, can you explain this? I do have a gadget in cig lighter that shows the charging voltage.

The alternator was replaced a couple of months ago. The el power service light came on once since but not again.

The old one regulator failed and was charging high voltage before failing completely.

So maybe it could be something to do with alternator unit or installation? As probably a refurbished unit rather than brand new.

dc voltage will be reading ok and will still charge the battery ok, But it can make a lot of noise on the electronics, put your radio on am and tune so you do not get any stations, with the car running can you hear wine/humming and increasing as you rev the car?
Were are you , I can have a look at it for you?
also if you take it anywhere make shore they use a scope , not just a m-meter or Battery load tester
Dave

[ALBERT10]

Originally Posted by davebb

dc voltage will be reading ok and will still charge the battery ok, But it can make a lot of noise on the electronics, put your radio on am and tune so you do not get any stations, with the car running can you hear wine/humming and increasing as you rev the car?
Were are you , I can have a look at it for you?
also if you take it anywhere make shore they use a scope , not just a m-meter or Battery load tester
Dave

Funny you mention that, no noise on AM or standard FM untuned , but I have a wireless audio Bluetooth sender to an fm channel, with the sound turned up high and no music being sent I can hear a whine which alters pitch when you move accelerator.

Is this normal or a sign of a leaky diode? I don't think it used to do it ages ago.

Could this issue also be the cause of the auto box not changing up when it should after engine has been off?

Maybe I could disable alternator somehow to test it and see if fault disappears?

[davebb]

Hi you have a ecu that controls your auto box and like scannerdanners video shows it can mess up the speed sensor reading, as it is showing on your speedo,, I dont know if there is a control plug on your alternator to disconnect as in video, if you unscrew the main alternator power yes it will show you if that is the problem, but running the alternator with no load ie charging the battery, is not good for the alternator, and my make it fail, ok that is not a problem if that is the problem, but if it is not, It could be costly,
has anyone disconnected the alternator/or battery with the car running ?
with this alternator fitted?
it wil be easier to go to a bosch center or a good autolec or find some one near you with a scope, they must connect the scope to the +BATT post on the alternator not the battery,
Dave

[davebb]

Hi it should take any good motor mec, with a scope 10mins to test it , or 20mins having a cup of tea and a ****,and a fast test drive in your Car