Battery - Updated ECM and Alternator Pulley

9233mercedes01

REF. NO. MBNA 07.3/16a, 15/8a


TO:
OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE:
March 1992 (supersedes MBNA 07.3/16, 15/8, October 1991)


Revision:
Change to assembly procedure

SUBJECT:
MODEL 129.066
1. MODIFIED CIS-E CONTROL UNIT
2. MODIFIED ALTERNATOR PULLEY AND FAN

To improve the charging characteristics of the vehicle's electrical system the engine idle speed is increased in relation to the battery voltage. Two modifications have been introduced as a repair solution for vehicles up to chassis end number 032708. The installation of the new pulley and fan will correct complaints of a discharging battery.

1. Modified CIS-E Control Unit

As of chassis no. 032708, a new CIS-E control unit has been installed in production. This new control unit will raise the engine idle speed by approximately 100 rpm during periods of low battery voltage, thus increasing the output of the alternator. The system will switch the idle speed increase circuit on under the following conditions:

1. Engine coolant temperature between 60~C (140~F) and 110~C (230~F),
2. Transmission gear selector in a driving position, 3. Battery voltage is less than 12.5 volts for at least 20 seconds, 4. Engine speed rises above 900 rpm. (This is to prevent a sudden power surge that would be noticed if the engine were at idle.)

If the first 3 conditions are met, the CIS-E control unit enters that fact into memory, so that when the fourth condition is met, the idle speed increase system will be switched on.

The increased idle speed setting will remain in effect until any one of the following occurs:

^ The transmission gear selector is placed in "N" or "P".
^ The engine coolant temperature exceeds 110~C (230~F).
^ The ignition is switched off.

The new control units may be installed in earlier production vehicles.


Parts Information

Part Name Part Number

Federal version vehicles 012 545 22 32
California version vehicles 012 545 23 32


In Case of Warranty

Operation:
CIS-E control unit, install modified version according to S.I. MBNA 07.3/16a, 15/8a.

Damage Code Operation Number Time Model(s)
54481**





2. Modified Alternator Pulley and Fan

A newly developed alternator pulley and fan are now available as a spare part. The installation of these parts serve to increase alternator rpm, thus increasing the charging capacity of the system and should be done up to chassis end number 032708. It is imperative that this pulley only be installed on model 129.066, since other engines may be able to exceed the alternator's maximum rotational limits.


To install the new pulley and fan, it is necessary to remove the original pulley and fan. Remove the collar nut (1), spacer (2), pulley (3), shield (4) and fan (5). Discard the shield (4). To assemble the new alternator, install the new fan (5), its fins pointing toward the alternator. Now install pulley (3), followed by spacer (2) (only if required), and finally a new collar nut (1). (Figure 1)





Tighten the nut to 70 +/- 5 N-m with a torque wrench (Figure 2).

Note:
The pulley is painted after manufacture. Therefore, it may be necessary to remove excess paint from the shaft hole to assure a proper fit.


Parts Information

Part Name Part Number

Pulley 119 155 09 15 05
Fan 000 155 99 18 05


In Case of Warranty

Operation:
Alternator pulley, install modified version according to S.I. MBNA 07.3/16, 15/8.

Damage Code Operation Number Time Model(s)
15111** 02-1523 0.4 hr. 92