Conversion of vehicles with CAT. to versions without CAT. - ra49lh1040001x(0001)

Engine 104 LH-Injection 

Operation No. of operation texts and operation values or standard texts and flat rates

Vehicles fitted with a catalytic convertor (KAT, code 620) can be converted to the version without KAT.

1. Disconnect battery.
2. Remove catalytic convertor (see 49-5531 , section A).
3. Install exhaust system without catalytic convertor (see 49-5531 , section B).
4. Cut off cable at the connector of the lambda sensor (G3/2x1).
   NOTE: Connector remains plugged in up to the insulation.
   Fig 1: Identifying Lambda Sensor

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5. Unplug all the control units from the module box using special tool 140 589 01 33 00. Remove module box.
6. Make up wiring harness as described in step  17.
   Fig 2: Identifying Hot Wire (LH) Control Unit, ABS/ASR Control Unit And Base Module

   Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
7. Run the yellow/green cable of the shop-made wiring harness through the side rubber grommet into the module box. Crimp small flat connector (003 545 51 26) onto the cable and press into the light green LH control unit coupling (without CAN) in slot 7. Cut off cable for air pump actuation from the light green coupling, slot 19, and cable for transmission shift-point retard from slot 20 about 30 mm behind the flat connector with pliers and insulate at both ends.

   Seal rubber grommet with silicone! 

8. Install module box.

   Exchange LH control unit (N3/1) and reinstall all the control units.

   If the part numbers listed in the table are installed (as of model year 1992), the control unit should not  be exchanged.

   Fig 3: Identifying LH Control Unit And Electronic Accelerator Pedal/Tempomat Cruise Control Control Unit

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9. Unplug LH resistance trimming plug (R17/2). Open coupling. Solder brown/white cable of the CO potentiometer (R33) to the brown/white cable in the coupling of the LH resistance trimming plug (R17/2). Plug in new resistance trimming plug (R17/2).
   Fig 4: Identifying LH Resistance Trimming Plug

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10. Install CO potentiometer (R33) behind the right head lamp unit. Plug connector of the shop-made wiring harness to (R33)
    Fig 5: Identifying CO Potentiometer

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11. Exchange EZL/AKR ignition control unit (N1/3) if the ignition control unit installed does not have the part no. 012 545 69 32.
12. Exchange EZL/AKR resistance trimming coupling (R16/2).
    Fig 6: Identifying EZL/AKR Ignition Control Unit And EZL/AKR Resistance Trimming Coupling

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13. Stick new engine data information plate over previous engine data information plate (see list of parts supply).
14. Connect battery.
15. Code radio.
16. Run engine to warm it up to an oil temperature of 60° - 80°C and check idle speed emissions level, adjust if necessary (Diagnosis Manuel Engine, Volume 1, Section "B").
    Fig 7: Checking Idle Speed Emissions Level

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17. Shop-made wiring harness 

    Contacts 2 and 3 in the coupling of the CO potentiometer (R33) must be bridged.

    NOTE: When performing the conversion work, always observe the relevant national regulations regarding vehicle registration.

Fig 8: [Identifying Shop-Made Wiring Harness Dimension]

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Converting KAT vehicles to vehicles without KAT:

02-4914-01 Basic operation

Special tool 

Fig 9: Identifying Special Tool (140 589 01 33 00 07)

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