The test module of the Lambda probes is present since MsV70 DME generation, it can be found in ../F9 group. Also DME of MSD80 series has this module available, true thou – only for N53 series engines. The reason is simple – this module provides management of 4 probes and mixed check-up of their connections. As you know, the N43 series engines have only 2 or 3 Lambda probes. Accordingly – the test module can not function normally.
How to work with the test module of the Lambda probes?
a) turn on and warm up the engine;
b) make sure, that all Lambda probes are getting heated, open ..F5/F6
both upper lines of the menu: heating of the probes. If the probes are heated, indications of all bars should be in range of 30 .. 70%. If the probes are not heated – continue to warm up the engine. If even with a warmed-up engine the heating of the probes doesn’t start, solve the problem (unfinished adaptations; incorrect encoding of the injectors etc.);
c) open test module of the Lambda probes ../F9/F3;
d) press F1 to start the test sequence.
Here, an example, how does the correct performance of the test block looks like.
Attention! The data during the performance of the test block are very important, not only data after the test block is finished. So – observe the indications of the probes, they have to correspond to the video above!
What does this test module do?
Stage 1 (video: 0:03 .. 0:26). DME enriches the mixture for 10% in the 1-st bank, but in the 2-nd bank – reduces the fuel injection for 10%. In this stage:
- the wideband probe of the 1-st bank has to indicate Lambda around 0.90 (+/-0.02), but the wideband probe of the second bank should indicate Lambda 1.10 (+/-0.02);
- the control probe of the 1-st bank has to confirm a rich mixture, its voltage has to be >0.80V, but the control probe of the 2-nd bank has to confirm a lean mixture, its voltage has to be <0.10V.
Stage 2 (video 0:27 .. 0:50). DME enriches mixture for 10% in the 2-nd bak, but in the 1-st bank – reduces fuel injection for 10%. In this stage:
- the wideband probe of the 1-st bank has to indicate Lambda around 1.10 (+/-0.02), but the wideband probe of the 2-nd bank has to indicate Lambda 0.90 (+/-0.02);
- the control probe of the 1-st bank has to confirm a lean mixture, its voltage has to be <0.10V, but the control probe of the 2-nd bank have to confirm rich mixture, its voltage has to be >0.80V.
This test module allows identifying the problems of the Lambda probes, for example:
- incorrect indications of the wideband probes (for example, due to a damaged trim resistor in the plug);
- mismatched places of wideband probes (can be done easily, because the plugs of probes are identical);
- mismatched places of control probes (can be done, although the plugs of the probes are different. It is possible to confuse the places if both control probes are being replaced and the probe, intended for the 1-st bank, is placed in the 2-nd bank, and vice versa);
- clogged and damaged (unable to generate the voltage) control probes.
