Electronic Throttle Actuator: Service and Repair
Removing And Installing/replacing Throttle Actuator (S62)
Switch off ignition.
Remove and install intake air manifold.
Disconnect plug connections (1).
Unclip cables (2) from cable guides.
Disconnect plug connections (1) on left knock sensor pair.
Disconnect plug connection (1) on throttle actuator.
Unhook cable duct (2) from mounts and raise approx. 2 cm.
Installation:
Check seating of rubber grommet on ignition coil cable.
Unclip cable strip (3) from injector valves, push upwards and tie back with cable ties (e.g. to engine hood).
Unhook pull rods (1) at ball heads on servomotor side.
Release screws (2).
Lift out injection pipe (3).
Installation:
Check sealing rings on fuel injectors for damage, replace if necessary.
Coat sealing rings with anti-friction rubber coating (e.g. petroleum jelly).
Release screws (1).
Unclip plug (2).
Lift out throttle actuator (3).
NOTE: Once the throttle actuator has been installed, the two cylinder banks must be synchronized with each other.
Caution!
In the event of any work which results in changing the basic setting of the throttles, it is necessary to carry out complete throttle basic setting.
If it is assured that the basic setting of the throttles has not been altered, it is sufficient to synchronize the two cylinder banks with each other as described below.
Synchronizing cylinder banks with each other:
NOTE:
This synchronization must be carried out if the:
1. pull rod has been replaced
2. throttle actuator has been replaced
NOTE: Remove the sealing flange so that it is possible to measure the full throttle opening (when setting the full load adaptation stop) with a standard slide caliper.
Remove and install sealing flange for left intake air manifold.
Prepare special tool kit 13 0 150:
Insert extension pin (1) into dial gauges.
Position dial gauge plates on throttle body of cylinders 2 and 3 and throttle body of cylinders 6 and 7. Mount dial gauges with inserted extension pins in dial gauge plate supports for measuring at throttle bodies 3 and 6.
If necessary, press pull rods off ball heads on servomotor side.
NOTE:
To simplify synchronization, correct height of dial gauges in such a way that large needles point upwards.
Turn dials on both dial gauges so that large needles point to zero.
Gently open and close each throttle bank several times to check if the large needles are always pointing to zero.
If necessary, correct dials.
Caution! After unclipping pull rods on throttle side, return throttles slowly to stops.
NOTE:
If the pull rod length has to be checked or adjusted, also press the pull rod off the ball head on the throttle side. Open throttles to do so.
Initial adjustment of pull rod length (center distance of ball sockets):
1. Non-adjustable pull rod (cylinder bank 1-4): 131.7 ± 0.4 mm
2. Adjustable pull rod (cylinder bank 5-8): 133 ± 0.8 mm
NOTE: Due to tolerances, the adjustable pull rod is installed on some vehicles for both cylinder bank 1-4 and cylinder bank 5-8.
Clip in non-adjustable pull rod (1) on throttle and servomotor sides.
Clip in adjustable pull rod (2) on throttle side and rest against ball head on servomotor side. If necessary, correct length of adjustable pull rod by turning hexagon head so that ball socket is centrally aligned to ball head.
Then clip in adjustable pull rod (2) on ball head on servomotor side.
NOTE: Because of the closing force of the return spring in the servomotor, one or both dial gauge(s) can display a slight deviation from zero (approx. 0.01 mm). Do not correct gauge dials.
Connect servomotor to engine wiring harness.
Activate servomotor by means of DIS Tester or MoDiC to specified value 1 %.
Caution!
Do not open throttles by hand.
Servomotor shaft with twin lever would thus receive a different radial position. This would result in an incorrect measurement result and incorrect throttle setting.
When the servomotor is activated at 1 %, throttles 3 and 6 are opened to such an extent that the dial gauges indicate a change between 0.2 mm and 0.4 mm. Check whether both dial gauges indicate the same value.
If necessary, turn hexagon head (1) on adjustable pull rod slightly until both dial gauges indicate the same opening value for throttles 3 and 6.
Enter specified value of 0 % and re-enter specified value of 1 %. Check whether both dial gauges indicate the same opening value for throttles 3 and 6.
Deviation between both dial gauges must be less than 0.03 mm.
Adjusting full-load adaptation stop:
Activate servomotor until throttles are fully open and stop screw (1) rests against stop lug.
Turn stop screw to set measurement (A) of 24.2 mm ± 0.5 mm.
Carry out measurement on all throttles on cylinder bank 5-8. Activate servomotor and check whether measurement (A) is in tolerance range on all 4 throttles 5-8.
NOTE:
Throttles 5 to 8 are opened here beyond the vertical position.
Throttles 1 to 4 open noticeably less. Do not correct.
NOTE: If measurement (A) = 24.2 mm ± 0.5 mm cannot be adjusted, the non-adjustable pull rod must be replaced by an adjustable pull rod and the supplementary work carried out.
Caution! As the engine wiring harness is only partially mounted, fault messages are stored in the DME control unit.
NOTE:
Interrogate fault memory of DME control unit.
Check stored fault messages.
Rectify faults.
Now clear the fault memory.