Wk4522
New Member
Hi all,
Wondering if anyone can help me with the weirdest abs issue i am having.
Abs/esp/parking brake malfuntion with associated lights on dashboard, speedo does not work sometimes and usually kicks in and out when doing a full lock or on hard acceleratiom buy abs lights remain.
VCDS has no communication with abs unit, a few times life has come back to the abs unit and lights turn off and vcds can read codes, this happens very randomly
So far the following i have done.
1. Checked wiring on abs plug three main power wires and ground all working no breaks and have 12v battery power or there abouts (11.8v)
2. Wiring checked on passenger wing for breaks all is fine.
3. Used abs pump plugged in to see if pump ecu issue (connector plugged in only not plummed in properly just to rule it out), still no communication, i have tried 2 abs pumps so it cant be the pump
4. Used a test light to check load, this is where it gets interesting, when test light is plugged in to any of the power wires going to the abs plug the voltage drops to 0v, take the test light off and u have 12v again. So at this point i thought must be resistance in the wires but this didnt make sense since its present in all 3 power wires unless they are linked somewhere ?
5. I plugged in the used abs unit and hard wired the power cables to the positive on the battery with a fuse, ignition on and all is fine and i can connecr vcds
Absolutely stumped by the issue as u can see i have tried alot to investigate but cant seem to see what would cause this ?
Vcds abs controller codes:
00446 - function limitation due to under voltage
002 - lower limit exceeded
U0121 - no communication with abs module
Wondering if anyone can help me with the weirdest abs issue i am having.
Abs/esp/parking brake malfuntion with associated lights on dashboard, speedo does not work sometimes and usually kicks in and out when doing a full lock or on hard acceleratiom buy abs lights remain.
VCDS has no communication with abs unit, a few times life has come back to the abs unit and lights turn off and vcds can read codes, this happens very randomly
So far the following i have done.
1. Checked wiring on abs plug three main power wires and ground all working no breaks and have 12v battery power or there abouts (11.8v)
2. Wiring checked on passenger wing for breaks all is fine.
3. Used abs pump plugged in to see if pump ecu issue (connector plugged in only not plummed in properly just to rule it out), still no communication, i have tried 2 abs pumps so it cant be the pump
4. Used a test light to check load, this is where it gets interesting, when test light is plugged in to any of the power wires going to the abs plug the voltage drops to 0v, take the test light off and u have 12v again. So at this point i thought must be resistance in the wires but this didnt make sense since its present in all 3 power wires unless they are linked somewhere ?
5. I plugged in the used abs unit and hard wired the power cables to the positive on the battery with a fuse, ignition on and all is fine and i can connecr vcds
Absolutely stumped by the issue as u can see i have tried alot to investigate but cant seem to see what would cause this ?
Vcds abs controller codes:
00446 - function limitation due to under voltage
002 - lower limit exceeded
U0121 - no communication with abs module