Oxygen Sensor: Service and Repair

1 - Cylinder head
2 - Exhaust manifold seal
3 - M8 fastening nut; replace
4 - Exhaust manifold
5 - Flange gasket; replace
6 - Primary catalytic converter cylinders 1 2 and 3
7 - Primary catalytic converter cylinders 4 5 and 6
8 - Oxygen sensor in front of catalytic converter cylinders 1 2 and 3
9 - Oxygen sensor in front of catalytic converter cylinders 4 5 and 6
10 - (Main) catalytic converter
11 - Fastening screws M8
12 - oxygen sensor behind catalytic converter, cylinders 1, 2 and 3
13 - oxygen sensor behind catalytic converter, cylinders 4, 5 and 6
14 - Heat shield
15 - Fastening screw M8
16 - Fastening screws M8 for intake distributor
17 - Support for intake distributor
18 - Side fastening screws M8 for intake distributor

Preliminary work
ATTENTION
- Danger of burns from hot exhaust system.
- Only remove the exhaust system once it has cooled down.
- Wear protective gloves.

Note Please read the most important working regulations and warning notes.

1. Move bonnet to service position using bonnet stay 9704.
2. Put on the protection covers.
3. Remove right-hand engine compartment covers.



4. Pull the design cover vertically upwards and off.

Tools and materials

Special Tools - Oxygen Sensors:

Accessory for torque wrench:
- Open ring wrench angled various lengths.

Removing
ATTENTION
- Material damage can be caused by interchanged oxygen sensors!
- Change in emissions.
- Check Engine light comes on.
- The connector color of the oxygen sensor cable for the oxygen sensor behind the catalytic converter must match the color of the oxygen sensor cable plug of the oxygen sensor ahead of the catalytic converter in the same exhaust assembly (brown to brown and black to black).
- Do not interchange oxygen sensors.





Note Cable plugs 1 and 2 belong 10 (he oxygen sensors behind catalytic converter wire plugs 3 and 4 belong to the oxygen sensors in front or catalytic converter The colors of the cable plugs are the same for each exhaust assembly.

Note Mark oxygen sensors as you unscrew them so that the oxygen sensors are not confused.







1. Disconnect cable plugs of oxygen sensors ahead of catalytic converter -3 and 4- and expose them.



2. Unscrew both oxygen sensors with a ring or open-ended wrench -1-.

Installing
1. Position oxygen sensors by hand and screw in as far as possible.



2. Position oxygen sensors behind catalytic converter -1- by hand and screw in as far as possible.
3. Tighten oxygen sensors using special tool. (37 ftlb.)



4. Lay oxygen sensor cable and press into clips. Fit cable plug -3 and 4-.

Subsequent work
1. Fit engine compartment covers.
2. Install design cover.
3. Fasten bonnet.