O2-sensor heating - fault code description ME-SFI

AD07.61-P-4000-08AA

O2-sensor heating - fault code description ME-SFI



O2 sensor heater (G3/3 to G3/6), heat output is too low

1A

Fault code

( Readout on generic scan tool)

P2008 Right O2 sensor upstream of TWC (G3/4) (P0135)

P2009 Right O2 sensor downstream of TWC (G3/6) (P0141)

P2088 Left O2 sensor upstream of TWC (G3/3) (P0155)

P2089 Left O2 sensor downstream of TWC (G3/5) (P0161)

1B

Engines 112, 113 as of 1/01

Fault code

( Readout on generic scan tool)

P2008-[8] Right O2 sensor upstream of TWC (G3/4) (P0135)

P2009-[8] Right O2 sensor downstream of TWC (G3/6) (P0141)

P2088-[8] Left O2 sensor upstream of TWC (G3/3) (P0155)

P2089-[8] Left O2 sensor downstream of TWC (G3/5) (P0161)

2

Fault storage

Actuation of the engine diagnosis indicator lamp (EURO3/4) or

CHECK ENGINE (MIL) 

after expiry of test duration and fault

following two successive driving cycles with faults

3

Checking frequency

Continuous

4

Checked signal or status

Internal resistance of the Nernst cells (generate the O2 sensor signal)

5

Fault setting conditions

O2 sensors upstream of TWC

O2 sensors downstream of TWC

OK if the calculated resistance value for a hot O2 sensor is 130 to 580 Ω (model 170: 130 to 480 Ω).

OK if the calculated resistance value for a hot O2 sensor is 160 to 1020 Ω (model 170: 160 to 770 Ω).

6

Check prerequisites

Exhaust and catalytic converter temperature 380 to 560°C

7



The internal resistance of Nernst cells is used as a criterion for the testing.

The internal resistance of Nernst cells must be within tolerance for the specified exhaust and catalytic converter temperature.

If a fault on voltage supply for O2 sensor heater is also stored then first check the voltage supply (connector, line, fuse).

In cases of a fault on the O2 sensor heater check:

1) Connector, line and fuse.

2) For a short circuit to ground: measure the resistor between the O2 sensor housing and the sensor heater (connection 1 or 2). Replace the O2 sensor if the resistance is less than 100 Ω.

3) For a short circuit to battery voltage: check the cold resistance (+25°C) of the sensor heater between connection 1 and 2. Replace the O2 sensor if the resistance is less than 4.5 Ω.

4) For line discontinuity: check the cold resistance (+25°C) of the sensor heater between connection 1 and 2. Replace the O2 sensor if the resistance is greater than 12 Ω.



Use of cleaning or greasing fluids (sprays) and evaporating greases on the O2 sensor or the screw-in thread is not permissible. The screw-in thread must only be lubricated using the released grease.

Broaching of the sensor lines is not permissible.