Checking the heating of the lambda probe
Since the lambda probe normally only works when hot, it is additionally heated when the engine warms up. Thanks to this, the lambda control begins to function normally after 1-2 minutes after starting the engine. If, in addition to checking the CO content, the heating of the lambda probe is checked, it can be assumed that the lambda control is working.
Check the security of the lambda probe in the front exhaust pipe.
Screw the lambda probe connector onto the bulkhead (Figure 2210).
1 Lambda probe power connector (-)
2 Lambda probe power connector (+)
3 and 4 Lambda probe heating sockets
Checking the heating of the lambda probe: Connect an ohmmeter to slots 3 and 4 (from the connector side of the lambda probe) and measure the resistance. Specification: max. 5 ohm, otherwise replace lambda probe.
Replacement
To replace the lambda probe, you must purchase a special BMW thread paste. In addition, pay attention to the fact that the lambda probe does not touch the body of the probe from the front.