Remove/install motor control unit of electrical power steering (ES) - AR46.20-P-0701NKB

MODEL 117, 156, 176, 242, 246 

Shown on model 246.2 

Fig 1: Electrical Power Steering Motor Control Unit Remove/Install Components - Shown On Model 246.2

Courtesy of MERCEDES-BENZ USA

	Note on high-voltage on-board electrical system		AH54.00-P-0010-01A
	Information on preventing damage to electronic components due to electrostatic discharge		AH54.00-P-0001-01A
	Note on high-voltage battery		AH54.10-P-0006-01MEV
	Remove/install
1	Perform disable for the high-voltage on-board electrical system	Model 242 with engine 780
			AR54.10-P-1150NKE
2.1	Remove bottom engine compartment paneling	Model 117 with engine 133, 270 Model 156 (except 156.912) Model 176 with engine 133, 270 Model 242 with engine 270, 780 Model 246 with engine 270
			AR61.20-P-1105NKB
2.2	Remove bottom part of soundproofing	Model 117 with engine 607, 651 Model 156 with engine 607 Model 176 with engine 607, 651 Model 246 with engine 607, 651
			AR94.30-P-5300NKB
3	Turn front wheels to straight-ahead position and fix steering wheel at center position	Retainer device	Figure
4	Disconnect electrical connectors (2) from electrical power steering control unit (N68)	Observe routing of electrical wiring harness.
5	Detach corresponding heat shield and place to one side	Model 176 with engine 607	AR46.20-P-0602NKA
		Model 117, 156, 176, 246 with engine 270, 651 (except 651.930) Model 242 with engine 270.920	AR46.20-P-0602NKB
6	Remove bolts (3) from electric power steering actuator motor (A91m1)	Screw/bolts (3) must be replaced.
		Bolt, motor controller unit (ES) to rack-and-pinion steering	*BA46.20-P-1003-01I
7	Remove electric power steering actuator motor (A91m1) from rack-and-pinion steering (1)	Sealing ring (4) must be replaced. Make sure that the sealing ring (4) is seated correctly.
8	Use lint-free rag to protect rack-and-pinion steering (1) and electric power steering actuator motor (A91m1) against dirt.	Soiling on the inside will result in destruction of the rack-and-pinion steering (1) or the electric power steering actuator motor (A91m1).
9	Check damper coupling (5)	Check damper coupling (5) is correctly seated. If damage is present ↓ Replace damper coupling (5)
10	Install in the reverse order
	Initial startup
11	Slowly turn steering wheel to and fro out of center position by 2°	The stabilizer bar in the steering gear must be released before the calibration.
12	Connect diagnostic system
			AD00.00-P-2000-04A
13	Calibrate torque sensor of electric power steering actuator motor (A91m1)	Only after replacing electric power steering actuator motor (A91m1). No work should be performed on the vehicle for the duration of the calibration procedure. Otherwise, the comparison may be negatively influenced.

STEERING GEAR

Number	Designation		Model 117	Model 156
BA46.20-P-1003-01I	Bolt, motor controller unit (ES) to rack-and-pinion steering	Nm	23	23

STEERING GEAR

Number	Designation		Model 176, 246	Model 242
BA46.20-P-1003-01I	Bolt, motor controller unit (ES) to rack-and-pinion steering	Nm	23	23

Fig 2: Identifying Retainer Device (129 589 01 21 00)

Courtesy of MERCEDES-BENZ USA