Esp light

[Spenman23]

Hi I have a 2013 DS3 1.6 petrol and when starting it comes up with esp fault on dash and display . The only fault codes present are u1321and u1121 both are in the abs module . Power steering module shows no codes . I have changed the rack which contains the module and steering angle sensor. Tried to carry out steering angle rest and calibration still same fault . No other codes or faults stored in any ECUs It has a brand new battery and charging ok. Anyone any ideas ? Thanks in advance for any help given .

[GiveMeABreak]

Both these are communications faults, so I would be checking the CAN network first before replacing parts. But as you've replaced the rack (and we assume the correct part as these are configured differently for each vehicle and engine), then that would more likely look like a problem with the with CAN network wiring or connectors. Don't overlook the actual physical connectors, as the pins can become loose - all it takes is one of these to break contact and that can cause the comms issues....

Fault Code:	U1121
Description of Fault:	Fault no communication with the electric power steering ECU. No signal. Information from the power steering ECU absent for more than 500 ms.
Conditions for Fault to clear:	After switching the ignition off and then back on
Downgrade Modes whilst Fault is active:	Cutting of all ESP operations Switching on of the warning lamp and/or warning message: Warning lamp ESP
Symptoms:	Illumination of the ESP indicator light
Suspect Areas:	Supply of electric power steering CAN network Electric power steering ECU

Fault Code:	U1321
Description of Fault:	Electric power steering operating fault. Reception of invalid information. Information from the power steering ECU absent for more than 500 ms.
Conditions for Fault to clear:	After switching the ignition off and then back on
Downgrade Modes whilst Fault is active:	Cutting of all ESP operations [*]Switching on of the warning lamp and/or warning message: Warning lamp ESP
Symptoms:	The indicator light ESP comes on
Suspect Areas:	Supply of electric power steering CAN network Electric power steering ECU