Test and Measurement Forum

Hello everyone,

I just need to know what are the suitable probes for automotive applications. I mean, almost every connector has waterproof connections. How should I proced for example in measuring a lambda signal? Or TPS signal ? Am I allowed, or is it OK in using a needle probe or a piercing probe. Does this affect and compromite the waterproof feature for that wires ?

Thank you for your support,

Bogdan

Hello, thanks for your post.

Within the Pico automotive kit we have many options for connectivity. The preferred method is to use the acupuncture probes to back pin a connector, this is done by sliding down the wire between the silicone rubber boot within the connector body. The other option is to pierce the wire insulation as you mention, this is a good way of making a secure connection but it is important to seal the wire after the connection is removed to avoid moisture ingress.

The other option is to use a breakout lead set as in the link below this enables easier connections in some cases and also puts you in circuit for current measurements, the only downside is that this is disturbance testing and could potentially mask the fault you are trying to find.

http://www.picoauto.com/breakout-lead.html

If you need anything further please do not hesitate to ask.

Regards,

Matt

Thank you, Matt,

So, in my oppinion the best metods are the acupuncture back probing ( if this not compromise the waterproof feature of the connector; I don't know .... ), or to use breakout lead set .

Another questions is if I had to measure the sensors aor the actuators at the ECU side of the wire it is OK? What is the suitable metode then ?

Finnaly, I would like to ask you what is the difference between visualising a lambda gouge signal on a common scan tool vs. an oscilloscope? So, it is posible to miss something on the scan tool? It is about resolution or mesuring priciple ?

Thank you for your support,

Bogdan

Hello, thanks again for your post.

Yes it is certainly OK to measure a signal at the ECU, this will be the actual information that the ECU is seeing and using to run the vehicle.

An excellent example was a suspected faulty crank sensor, the sensor was back pinned directly and the signal was absolutley fine, but the vehicle would not start, checking the crank sensor wiring at the ECU revealed a very corrupted signal, further investigation uncovered a damaged section of wiring loom!

To be completly honest connecting to the ECU wiring will depend on the type of multi plug used by the manufacturer but if you have a PIco kt you will find a suitable probe for most situations.

The difference between a scope signal and live data is that the scope is showing the real world signal in real time. The data from the graphing scan tool is filtered and possibly adjusted and is also not in real time due to the information being processed.

Hopefully the above is of use to you and as always if you have any more question do not hesitate to ask.

Regards,

Matt