Date: January 10, 2008
Order No.: P-B-42.45/95
Supersedes:
Group: 42
SUBJECT:
All Model 129
All Model 140
All Model 170, As of March 18, Production
All Model 202 and 208, As of August 1, 1999 Production
All Model 210, As of July 1, 1999 Production
"ESP - Visit Workshop" Displayed in Instrument Cluster / ESP Indicator Lamp Illuminated
If you receive customer reports in the above model vehicles that the message "ESP - Visit Workshop" is displayed within the instrument
cluster or the ESP indicator lamp is illuminated and the fault codes listed below are stored within the ESP control unit, perform the following
steps to resolve.
^ C1140 - N49 (Steering Angle Sensor) Steering angle sensor is not initialized/is faulty
^ C1504 - System faults : Steering angle sensor is not initialized
Note:
Mercedes Benz C 43 AMG (202.033) V8-4.3L (113.944) Page 312
Fault codes C1140 and C1504 are typically due to either an under-voltage condition or the incorrect installation of the steering angle
sensor.
1. By using Star Diagnosis, check the steering angle sensor's actual values by slowly rotating the steering wheel to the left stop and then to the
right stop. The steering angle sensor value (XXX�� degrees) should continuously change while turning the steering wheel.
2. If the value does not change, replace the steering angle sensor. Refer to WIS document AR46.10-P-0300B. Refer to EPC for the latest steering
angle sensor part number.
3. Read out the ESP fault memory and check if the time at which the entry was recorded matches the time frame stated by the customer (when the
ESP indicator lamp came on). If the fault occurred during initial vehicle start-up, then generally the cause will be due to an under-voltage
condition. Check the frequency counter of fault codes C1140 and C1504 by selecting F8 key in Star Diagnosis. To check the frequency count
by using Star Diagnosis, select menu item "Fault Freeze Frame Data" after choosing the desired fault code.
Note:
The frequency counter counts down from 255 to 0. For example, a value of 255 means that only 1 ignition sequence has occurred since the
fault (new entry) and a value of 1 means that 255 ignition sequences had occurred since the fault (old entry).
4. For models 170/202/208/210, use the procedure listed below to check the steering angle sensor supply voltage. Correct any deviations
encountered.
^ Measure PIN 3 (ground) at the steering angle sensor with respect to the battery voltage (12-14 V) or with respect to the ground terminal of
the battery (1 ohm).
^ Measure PIN 4 (power supply for terminal 30) at the steering angle sensor with respect to PIN 3 at the steering angle sensor (12-14 V)
^ Measure PIN 2 (power supply for terminal 87) at the steering angle sensor with respect to PIN 3 at the steering angle sensor, where it is
12-14 V with the ignition on and 0 V with the ignition off.
5. For models 129 and 140, reference the Diagnostic Chassis Manual volume 3, chapter 10.1, test steps 29.1 and 29.2 in order to check the
steering angle sensor supply voltage. Correct any deviations encountered.
6. If the problem persists, check if the steering angle sensor is installed correctly by measuring dimension "A" between the steering angle sensor
and clock spring at 5 different locations around its circumference (Figure 1) by using a feeler gauge (W129 589 03 21 00).
Note:
Press the rotor of the clock spring contact towards the steering shaft when measuring. Dimension "A" must measure between 3.0 mm and
5.5 mm. The steering angle sensor is very sensitive to tolerance deviations because of its design. Therefore, ensure that the measurements
are performed very precisely.
7. If the measured value deviates from the acceptable range, either readjust the 3-point support for the turn signal switch module or replace the
jacket tube in order to achieve the specified values.
Note:
Only in the rarest of cases does replacing the steering angle sensor resolve this issue. This issue is generally caused by either supply
voltage or tolerance deviations. Additionally do not replace the ESP control unit or the instrument cluster to resolve this issue.
Mercedes Benz C 43 AMG (202.033) V8-4.3L (113.944) Page 313
Special Tools
Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated
on January 10, 2008. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.
Note:
This document is not an exension of warranty coverage. Please check warranty coverage prior to claim submission.
In Case of Warranty, use the table.
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