mkl22

Have this weird behavior from the ABS DSC and TCS lights.

When i first start the car cold after resting a few hours or over night. the following happens.

1) turn ignition to on, the 3 warning lights turn on and then extinguish after 2-3sec.
2) as i crank the engine these 3 lights come on again and only extinguish after approx 1-2 sec after the engine has started.
3) everything is fine after that.

Before this, the lights used to remain off when i cranked the engine to start.

Also after driving for 10-15min of so and if i shut down the engine and restart. Turn the ignition to ON, the lights extinguish after 2-3sec and do not come on when cranking.

This leads me to believe that maybe a weak battery might be the cause of this. and this only happens after the car has been parked for a while.

All the other warning lights seem to operate as before.

Kinda weird that this happens. Car was not modified in any way including any LED lights

staticlag

sounds like a weak battery or a loose battery connection.

Uncivilizedracer

+. . . . 1

mkl22

yup probably a weak battery.

Check the batt and found the water level a bit low. supposed to be a maintenance free battery. but it still have fill holes that can be open if you tear the sticker covering them off. fill them back up but it still happens. looks like i might need to change batt soon.

mkl22

update:

New battery and still the same, but now only TCS and ABS lights. Found out it only occurs after i have parked the car overnight. maybe slightly cooler temps. But i live in Singapore which is at the equator so over night temps lowest is 24C. If i park at my office carpark from 930am to 630pm its fine.

also checked the parasitic draw and found it was 23mA. so within specs. also checked the lowest instantaneous voltage the battery drops to when you start the car, its 9.6V. but whether it happens or not, the voltage seen during starting is still 9.6V. so it doesnt seem that the battery is causing it.
The funny thing is that after you start in the morning and the lights flash, you shut down and then restart again immediately. the problem does not crop up anymore. if its was the battery, the battery would be the weakest after a start, before the alternator charges it.

this makes me think that it might be one of the ABS sensors. but then when the car is running there is no CEL or ABS/TCS lights coming on. all is fine.

Puzzling. maybe i should just ignore it

mkl22

13.8v to 14V or something like that, or was it 13.6v. its charging.

whitebeau

Don't the ABS go through a calibration diagnosis during startup? Since the TCS is reliant on the ABS, best method i can think to see whats triggering is to have a scantool to do a capture during startup.

My guess is one of the ABS sensors isn't finishing it's calibration, or isn't getting the expected response during calibration, then it loops into a retest before flagging a CEL. This is just a guess on how you can get it on initial start. 2nd+ starts on a warm cycle may have been able to actuate the 'boot test' so to speak.


How is your Brake fluid, is it low? recent brake fluid change? Alternate theory i'm having is an improper bleed, or brake fluid in need of change could cause a delay in the startup calibration the ABS goes through.

mkl22

Brake fluid is fine and the brakes have not been touched. Nor suspension was done which might have damaged the ABS sensor during the change. anyway brake fluid low will be denoted by the handbrake light and not ABS.

Also the system seems to calibrate fine as when i switch the key to the ON position all the lights light up and then go off after a few seconds. its only during cranking that TCS and ABS light up again and once the engine catches they go off within 1-2secs max. and this only occurs when i park overnight. As mentioned, parking from 930am to 630pm, this problem does not occur. also just checked the ABS sensors. none seems to be loose. fuses also seem fine.

Could this be linked to the steering juddering problem. my steering judders in early morning when its colder. have soldered the connectors and still the same. mostly likely i will need to replace the rack like many others in Singapore. no steering malfunction light is on.Probably the torque sensor is dying. mine is a end 03 build.

HiTMaNN

+1

mkl22

about the steering? it happened months back and still happening. this TCS/ABS thing only started recently.

you think there is a link?