Steering - Basic Knowledge - 211 Chassis: Other Mercedes-Benz E-class W211/S211

Steering wheel heater (LRH), function - GF46.11-P-0001T

MODELS 211.0 /2 /6 up to 31.5.04 with CODE (443) Steering wheel heater

Steering Wheel Heater (LRH) Function Diagram. Scheme 15

General information

In order to make hand contact more comfortable and safer at low temperatures, the steering wheel can be heated up via the steering wheel heater (LRH).

Operation takes place via the steering wheel heater switch (S59/1s2), control is taken over by the DC/DC converter control unit (N99).

The steering wheel heater (LRH) is operated with a voltage of 42 V or 48 V in order to produce the necessary output of 100 W. The voltage conversion is taken over by the DC/DC converter control unit (N99)

Scheme 16

Function requirements

1. Circuit 15R or circuit 15 ON
2. Interior temperature < 30°C

Switch on steering wheel heater (LRH)

1. Rotate the steering wheel heater switch (S59/1s2) upwards.
2. The signal is read in by the steering column module (N80) and transmitted via the CAN-B (CAN-B) to the DC/DC converter control unit (N99).
3. 48 V is applied to the heater coil (R22/4r1) by the DC/DC converter control unit (N99) via the steering wheel heater electronics (A74). In order to protect it from overheating, it is switched over to 42 V after 7 minutes. The temperate of the steering wheel rim is measured by the steering wheel heater electronics via the heater coil temperature sensor (R22/4b1)(A74) and used for the control.

The activated steering wheel heater (LRH) is displayed by the steering wheel heater function indicator (S59/1 e 1) in the steering wheel heater switch (S59/1s2)

Switching off steering wheel heater (LRH) manually

1. Turn the steering wheel heater switch (S59/1s2) downwards.
2. The signal is read in by the steering column module (N80) and transmitted to the DC/DC converter control unit (N99) via the CAN-B (CAN-B).
3. The DC/DC converter control unit (N99) deactivates the steering wheel heater (LRH).

Switching off the steering wheel heater (LRH) automatically

1. The maximum permanent heating time is 24 minutes. After this the heater coil (R22/4r1) is switched off by the DC/DC converter control unit (N99).
2. At interior temperatures higher than 30°C the steering wheel heater (LRH) is switched off in order to prevent overheating of the heater coil (R22/4r1). The interior temperature is transmitted by the overhead control panel control unit (N70) via CAN-B (CAN-B) to the DC/DC converter control unit (N99).

When the steering wheel heater (LRH) is deactivated the steering wheel heater function indicator (S59/1 e 1) in the steering wheel heater switch (S59/1s2) goes out

Diagnosis

Diagnosis for the steering wheel heater (LRH) takes place through the request "read out fault" in the DC/DC converter control unit (N99).

Reading in the steering wheel heater switch (S59/1 s2)

The position of the steering wheel heater switch (S59/1 s2) is read out by the steering column module (N80) and placed on CAN-B (CAN-B). As long as the steering wheel heater switch (S59/1 s2) is operated (turning up or down), the corresponding position is transmitted cyclically. The center position of the steering wheel heater switch (S59/1 s2) is not transmitted by the steering column module (N80).

Steering wheel heater (LRH), function - GF46.11-P-0001TA

MODELS 211.0 /2 /6 as of 1.6.04 with CODE (443) Steering wheel heater

Identifying Steering Wheel Heater Switch Location. Scheme 17

General

In order to make hand contact more comfortable and safer at low temperatures, the steering wheel can be heated up via the steering wheel heater (LRH).

Operation takes place via the steering wheel heater switch (S59/1 s2), control is taken over by the HS [SIH] and seat ventilation control unit (N25/7).

Function requirements

1. Circuit 15R or circuit 15 ON
2. Interior temperature < 30°C

Switch on steering wheel heater (LRH)

1. Rotate the steering wheel heater switch (S59/1 s2) upwards.
2. The signal is read in by the steering column module (N80) and transmitted via the CAN-B (CAN-B) to the HS [SIH] and seat ventilation control unit (N25/7).
3. The heater coil (R22/4r1) is supplied with voltage by the HS [SIH] and seat ventilation control unit (N25/7) via the steering wheel heater electronics (A74). The temperate of the steering wheel rim is measured by the steering wheel heater electronics via the heater coil temperature sensor (R22/4b 1)(A74) and used for the control (target temperature approx. 35°C).

Function indicator

The activated steering wheel heater (LRH) is displayed by the steering wheel heater function indicator (S59/1 e 1) in the steering wheel heater switch (S59/1 s2).

Switching off steering wheel heater (LRH) manually

1. Turn the steering wheel heater switch (S59/1 s2) downwards.
2. The signal is read in by the steering column module (N80) and transmitted via the CAN-B (CAN-B) to the HS [SIH] and seat ventilation control unit (N25/7).
3. The HS [SIH] and seat ventilation control unit (N25/7) deactivates the steering wheel heater (LRH).

The steering wheel heater function indicator (S59/1 e 1) in the steering wheel heater switch (S59/1 s2) goes out

Switching off the steering wheel heater (LRH) automatically

1. Once the maximum heating time has elapsed (continuous heat mode for 15 minutes) the HS [SIH] and seat ventilation control unit (N25/7) is shut off. The steering wheel heater function indicator (S59/1 e 1) goes out.
2. The HS [SIH] and seat ventilation control unit (N25/7) is shut off at an interior temperature higher than 30°C. The steering wheel heater function indicator (S59/1 e 1) remains active. The interior temperature is transmitted by the AAC [KLA] control and operating unit (N22) or by the comfort AAC control and operating unit (N22/7) via the CAN-B (CAN-B).
3. Circuit 15R is switched off. The timer control The timer control continues running for 5 minutes with circuit 15C <> On. If within this period circuit 15R is switched on again, the steering wheel heater (LRH) is also activated again.

Abort conditions

1. During the engine starting process. The steering wheel heater function indicator (S59/1 e 1) remains active.
2. In the event of undervoltage or overvoltage. The steering wheel heater function indicator (S59/1 e 1) flashes at 1.5 Hz and 50 % brightness.

Reading in the steering wheel heater switch (S59/1 s2)

The position of the steering wheel heater switch (S59/1 s2) is read out by the steering column module (N80) and placed on CAN-B (CAN-B). As long as the steering wheel heater switch (S59/1 s2) is operated (turning up or down), the corresponding position is transmitted cyclically. The center position of the steering wheel heater switch (S59/1 s2) is not transmitted by the steering column heater switch (S59/1 s2) is not transmitted by the steering column module (N80).

Storing Steering Column Function Diagram. Scheme 18

Identifying ESC [ELV] Motor Location. Scheme 19

Electrically adjustable steering column (ESC), function - GF46.15-P-0003T

MODEL 211.0 /2 with CODE (275a) Memory package (driver's seat, steering column, mirrors)

Identifying Steering Gear Ratio Shape And Angles Of Toothing. Scheme 20

Function

The electrically adjustable steering column (ESC) is controlled by the "Memory" system which comprises the following functions

1. Manual seat and steering column adjustment
2. Memory adjustment, driver-side (seat, steering column, outside mirror)
3. Memory adjustment, front passenger-side (seat)
4. Easy entry/exit
5. Mirror park position
6. Key-dependent settings

Manual steering column adjustment

The position of the steering column is adjustable manually via the electrical steering column adjustment switch (S59). The longitudinal and height adjustment can be regulated separately

1. the fore/aft position of the steering column
2. The height of the steering column

Steering column adjustment memory function

The memory function can be used to store different steering column positions. The positions are stored by means of the memory button in the left front door control unit (N69/1).

Easy entry/exit

The easy entry/exit function makes it easier for the driver to get in and out due to the steering column being moved into the upper locking position.

Easy entry/ exit can be activated in the instrument cluster

Storing steering column position, function - GF46.15-P-2003T

MODEL 211.0 /2 with CODE (275) Memory package (driver seat, steering column, mirrors)

Function

The current position is always stored

1. with the transition from terminal 15 to terminal 15R
2. upon receipt of a request to store a memory position
3. upon receipt of a request to adjust a memory position, even if the function easy entry/exit is switched off.

Before saving the position, the steering column must be moved to the desired position using the steering column adjustment switch (S59).

Save the steering column position as follows

1. First press the memory switch (S91/2s9) for t< or =40ms and release, then press the relevant position key of memory button 1, 2, 3 switch (S91/2s14) within t> or =3s of releasing the memory switch (S91/2s9).

The position of the steering column is stored in the driver-side front seat adjustment control unit with memory (N32/1).

On vehicles as of 1.6.07 an acoustic feedback takes place via a warning buzzer integrated in the instrument cluster (A1) when the steering column position is stored

Rack-and-pinion steering gear, function - GF46.20-P-1000-01T

Model 211

The drive pinion (4b) transmits the movement of the steering wheel to the gear rack (7) and then via the tie rods to the wheels.

The drive pinion has spiral splines. Because a number of teeth are always meshed at the same time, the rack-and-pinion steering is resistant to wear and has a very low noise level.

Identifying Drive Rack And Pinion. Scheme 21

Steering gear ratio and gear teeth

The variable steering gear ratio is achieved by means of the effective diameters (d1 and d2) resulting from the shape and angles of the gear teeth.

In the central area (X) the gear rack is indirect. The rack-and-pinion steering becomes increasingly direct in the outside areas (Y).

The difference between the gear ratio in the central area (X) and the gear ratio in the outside area (Y) amounts to approx. 15%.

Rack-And-Pinion Steering, Function Diagram (Illustrated On Model 220, Left Wheel Lock). Scheme 22

Rack-and-pinion steering play compensator, function - GF46.20-P-1100-03T

Model 211

Section View Of Power Steering Pump. Scheme 23

Function

The thrust piece (6c) ensures that the drive pinion (4b) and rack (7) mesh without any play.

Engine ON: Because the hydraulic steering assistance starts immediately, no steering play is noticeable.

Engine OFF: When steering, only a slight, gradually increasing torque is noticeable for a travel distance of approx. 50 mm. This is due to the slewing range of the torsion bar in the rotary valve and should not be confused with play in the steering gear. Only when the steering wheel is turned further does the drive pinion begin to roll across the gear rack, which can be felt on the steering wheel in the form of a slight pressure point and a more rapidly torque increase.

Rack-and-pinion steering damper, function - GF46.20-P-1200-02T

Model 211

Identifying Rack-And-Pinion Steering Damper Components - Shown Steering Left. Scheme 24

Shown steering left

Steering damper pressurized (I)

The high-pressure oil passes unrestricted through four holes in the perforated disk (5b) and past the return plate (5a) against the force of the return spring (5c) to one of the working cylinders.

Damped return pressure (II)

The oil flowing from the opposite working cylinder is forced through four other holes in the perforated disk (5b). This pushes up the disk spring (5d) and pumps the oil into the return line. This restricted pressure provides the required damping effect.

Rack-and-pinion steering overall system, function - GF46.25-P-0001T

MODEL 211 except CODE (213a) Speed-sensitive power steering

Identifying Rack-And-Pinion Steering Overall System Diagram. Scheme 25

Identifying Rack-And-Pinion Steering Components. Scheme 26

Rack-and-pinion steering straight-ahead driving function - GF46.25-P-3100B

MODEL 171.4, 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Shown on model 220

Rack-And-Pinion Steering Straight-Ahead Driving Function Diagram - Shown On Model 220. Scheme 27

The rotary valve is composed of the rotary slide (4k) with 6 control grooves with ground edges on its jacket surface, and the pilot bushing (4i) also with 6 control grooves corresponding to those on the rotary slide (4k).

One end of the torsion bar (4a) is pinned to the rotary slide (4k), and the other end to the drive pinion (4b). It holds the rotary slide (4k) in the neutral position when the steering wheel is not turned.

Rack-and-pinion steering straight-ahead driving function - GF46.25-P-3100P

MODEL 171.4, 203, 209, 211 except CODE (213a) Speed-sensitive power steering

Shown on model 203

Rack-And-Pinion Steering Straight-Ahead Driving Function Diagram - Shown On Model 203. Scheme 28

The rotary valve is composed of the rotary slide (4k) with 6 control grooves with ground edges on its jacket surface, and the pilot bushing (4i) also with 6 control grooves corresponding to those on the rotary slide (4k).

One end of the torsion bar (4a) is pinned to the rotary slide (4k), and the other end to the drive pinion (4b). It holds the rotary slide (4k) in the neutral position when the steering wheel is not turned.

Rack-and-pinion steering, function when steering - GF46.25-P-3400A

MODEL 171.4, 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Illustrated on model 220, left wheel lock

Rack-And-Pinion Steering, Function Diagram (Illustrated On Model 220, Right Wheel Lock). Scheme 29

Illustrated on model 220, right wheel lock

When the steering wheel is turned, the drive pinion (4b) rests on the rack (4j). The rotary slide (4k) is twisted against the surrounding pilot bushing (4i) by the torsion bar (4a), thus changing the relative positions of the control grooves. The high-pressure oil stream passes into the right working cylinder (left wheel lock) (I) or into the left working cylinder (right wheel lock) (II), causing the axial movement of the rack (4j) to the right or left.

The oil from the unpressurized working cylinder is displaced. It flows through the open return grooves in the pilot bushing (4i) back to the supply reservoir of the power steering pump.

Rack-and-pinion steering, function when steering - GF46.25-P-3400P

MODEL 171.4, 203, 209, 211 except CODE (213a) Speed-sensitive power steering

Rack-And-Pinion Steering, Function Diagram (Illustrated On Model 203, Left Wheel Lock). Scheme 30

Illustrated on model 203, left wheel lock

Rack-And-Pinion Steering, Function Diagram (Illustrated On Model 203, Right Wheel Lock). Scheme 31

Illustrated on model 203, right wheel lock

When the steering wheel is turned, the drive pinion (4b) rests on the rack (4j). The rotary slide (4k) is twisted against the surrounding pilot bushing (4i) by the torsion bar (4a), thus changing the relative positions of the control grooves. The high-pressure oil stream passes into the right working cylinder (left wheel lock) (I) or into the left working cylinder (right wheel lock) (II), causing the axial movement of the rack (4j) to the right or left.

The oil from the unpressurized working cylinder is displaced. It flows through the open return grooves in the pilot bushing (4i) back to the supply reservoir of the power steering pump.

Power steering pump, function - GF46.30-P-2100-01B

Models 203, 209, 211

Models 220, 230 except Code (487a)

Active Body Control (ABC)

Identification of power steering pump manufacturers

Models 220, 230

LF 30 = LuK Clutch and Transmission Systems

FP 42 = ZF (Zahnradfabrik Friedrichshafen)

Models 203, 209, 211 with diesel engines

LF 37 = LuK Clutch and Transmission Systems

FP 42Q = ZF (Zahnradfabrik Friedrichshafen)

Models 203, 209, 211 with gasoline engines

LF 30 = LuK Clutch and Transmission Systems

FP 42 = ZF (Zahnradfabrik Friedrichshafen)

c Unpressurized

f Pressurized

A To steering gear

B From supply reservoir

Basic function

The rotation of the drive shaft, and thus of the rotor, produces a centrifugal force which presses the blades on the rotor in the radial direction against the running surface of the non-moving cam insert. This is assisted by hydraulic oil, which travels from the pressure chamber via bores and grooves and against the internal end faces of the blades. Ten closed pump cells are thus formed between the ten blades of the rotor.

As the volume increases, oil is drawn up from the supply reservoir (B); as the volume decreases, oil is forced into the pressure chamber (A). Because the shape of the cam insert means that two suction and two pressure zones are opposite each other, each of the ten pump cells pumps twice its own volume for each rotation of the drive shaft.

Furthermore, this double arrangement of suction and pressure zones causes the radial hydraulic forces acting on the rotor to cancel each other out.

(Scheme 15) Quantity control valve (30t) open

Power Steering Pump, Function Diagram - Quantity Control Valve (30T) Open. Scheme 32

(Scheme 16) Quantity control valve (30t) closed

Power Steering Pump, Function Diagram - Quantity Control Valve (30T) Closed. Scheme 33

Oil volume regulation

The power steering pump is driven by the engine at alternating speeds. Power assistance however requires a constant oil flow. As more oil than is necessary is pumped at higher engine speeds, the surplus oil is fed back to the supply reservoir via the open quantity control valve (30t).

The quantity control valve (30t) thus ensures that the steering gear is supplied with a constant oil stream across the entire engine speed range.

Scheme 34

1. Engine ON, steering wheel not turned: The pressure oil produced by the rotor cells is fed via the calibrated bore hole (9a) to the steering gear and also via the bore (9b) to the spring chamber downstream of the quantity control valve (30t). The calibrated bore holes (9a, 9b) throttle the oil stream so that the oil pressure in the spring chamber downstream of the quantity control valve (30t) is lower than on the side of the high-pressure chamber. The quantity control valve (30t) opens (Scheme 15) and the surplus pressure oil flows back to the supply reservoir.
2. Engine ON, steering wheel turned: Because of the rising pressure downstream of the restrictor orifice (a), the pressure downstream of the quantity control valve also rises. The quantity control valve (30t) closes (Scheme 16) and remains in its basic position.
3. High engine speed: If the oil quantity increases as the engine speed rises, a greater pressure difference again occurs due to the calibrated bore hole (9a). The quantity control valve (30t) is forced against the spring (30s) and the surplus oil can flow back to the supply reservoir (Scheme 15) see scheme 35: Power Steering Pump, Function Diagram - Quantity Control Valve (30t) Open

Quantity control valve (30t) open

Pressure limiting

A pressure limiting valve (49d) is installed in the quantity control valve (30t) to protect the steering system against overloading. It opens at a pressure between 65 and 125 bar depending on the model of power steering pump.

This occurs, for example, at full steering lock, and is audible as a high-pitched whirring whistle.

Speed-sensitive power steering (SPS), function - GF46.50-P-0001A

MODELS 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Identifying Speed-Sensitive Power Steering (SPS) Function - Models 203, 209, 211 With Code (213A) And 215, 220, 230. Scheme 35

Shown on steering gear model 220

Identifying Speed-Sensitive Power Steering (SPS), Function Diagram - Shown On Steering Gear Model 220. Scheme 36

The speed-sensitive power steering (SPS) gradually increases the manual effort required to turn the steering wheel from when the vehicle is stationary up to a speed of approximately 100 km/h.

When stationary, the steering assistance is similar to that of the hydraulic power steering (without SPS function).

The operating parameter is the vehicle speed, which with the aid of the electronic systems, adjusts the hydraulic reaction by means of the SPS solenoid valve (Y10) in the speed range from 0 to approx. 100 km/h to suit the requirements.

The electronic control system is integrated in the traction system control module (N47).

SPS electrically controlled centering, function - GF46.50-P-2400AA

MODELS 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Function

The electronic control system of the speed-sensitive power steering is integrated in the traction system control module (N47). A certain manual force (K) is set at the steering wheel according to the speed of the vehicle. As the speed of the vehicle increases, the manual effort (K) required to turn the steering increases at the steering wheel (up to 100 km/h).

The driving speed calculated by the traction system control module (N47) is assigned a nominal current in a characteristic map. This current is then set in the SPS solenoid valve (Y10) (proportional solenoid valve) and influences the oil flow (hydraulic reaction) within the rack-and-pinion steering, and thus the manual force (K) required at the steering wheel.

Manual Force Graph. Scheme 37

The actuation of the SPS solenoid valve (Y10) is pulsed. The current is regulated by pulse-width modulation of these pulses.

SPS Solenoid Valve Pulse-Width Graph. Scheme 38

Speed-sensitive power steering, function with vehicle stationary - GF46.50-P-2500A

MODEL 171.4, 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Illustration shows rotary valve and control bush housing for models 215 and 220, left wheel lock

Identifying Rotary Valve And Control Bush Housing For Models 215 And 220, Left Wheel Lock. Scheme 39

Vehicle speed v = 0 km/h

The SPS solenoid valve (Y10) receives maximum current which closes it against the force of the integrated compression spring. The pressure ratios in the reaction chambers are identical, since the pressure oil supply is stopped. No force is exerted on the reaction balls (4) and no additional moment is produced on the v-shaped surfaces of the rotary valve (12).

The steering turns easily because the steering moment which the driver must apply to overcome the force of the torsion bar (10) is very low. The oil passes virtually unpressurized via the constant constriction orifice (8) to the supply reservoir of the power steering pump.

Speed-sensitive power steering at vehicle speeds 0-100 km/h when steering, function - GF46.50-P-2600A

MODEL 171.4, 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Shown: rotary valve housing and control bush housing, models 215, 220 left wheel lock

Identifying Rotary Valve Housing And Control Bush Housing, Models 215, 220 Left Wheel Lock. Scheme 40

Shown: rotary valve housing and control bush housing, models 215, 220 right wheel lock

Identifying Rotary Valve Housing And Control Bush Housing, Models 215, 220 Right Wheel Lock. Scheme 41

As the vehicle speed increases, the energization of the SPS [PML] solenoid valve (Y10) decreases continuously; this is opened by the force of the integral push spring. The regulated pressure is transmitted via the control spool (9) to the reaction balls (4), which causes the pressure acting on the v-shaped surfaces of the rotary slide (12) to rise. The force on the torsion bar (10) is thus further increased and the driver must operate the steering wheel with a higher steering moment.

The constant constriction orifice (8) reduces the regulated pressure from the SPS solenoid valve (Y10). This is then passed on as an almost depressurized backflow to the power steering pump reservoir.

Speed-sensitive power steering at vehicle speeds >100 km/h when steering, function - GF46.50-P-2700A

MODEL 171.4, 203, 209, 211 with CODE (213a) Speed-sensitive power steering

MODELS 215, 220, 230

Rotary valve and control bush housing for models 215 and 220 illustrated Steering left

Identifying Rotary Valve And Control Bush Housing For Models 215 And 220 - Illustrated Steering Left. Scheme 42

Vehicle speed v --> 100 km/h

The SPS [PML] solenoid valve (Y10) is energized to the minimum extent. This causes the maximum possible pressure from the SPS solenoid valve (Y10) to be directed via the control spool (9) onto the reaction balls (4), increasing the pressure acting on the v-shaped surfaces of the rotary slide (12) to the maximum.

The constant constriction orifice (8) reduces the regulated pressure from the SPS solenoid valve (Y10). This is then passed on as an almost depressurized backflow to the power steering pump reservoir.

SPS solenoid valve, function - GF46.50-P-5000-01B

Model 203.0 as of 01.08.01

Models 203.2, 203.7

Models 209, 211, 215, 220, 230

SPS Solenoid Valve Function Graph - Models 203.0 As Of 01.08.01, 203.2, 203.7, 209, 211, 215, 220, 230. Scheme 43

SPS solenoid valve (Y10) open

Scheme 44

SPS solenoid valve (Y10) closed

Identifying SPS Solenoid Valve Closed - Models 203.0 As Of 01.08.01, 203.2, 203.7, 209, 211, 215, 220, 230. Scheme 45

The electronics for actuation of the SPS solenoid valve (Y10) are integrated in the traction system control module (N47). The SPS solenoid valve (Y10) is actuated in pulses. As the vehicle speed increases, the current flow decreases and the SPS solenoid valve (Y10) gradually opens the control valve according to a characteristic (K) defined in the traction system control module (N47).

This regulates the oil flow and thus the torque to be applied to the steering wheel. When the SPS solenoid valve (Y10) is actuated with the maximum current (v=0 km/h), the control valve is closed.

No oil flows and the minimum steering wheel torque is set (situation for parking).