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Can lambda connection issues


Aidan99

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Hey, I am having trouble with my link g4x, can lambda connection. I have wired it up all correctly and the sensor is getting warm so I know it’s getting power (also checked with multimeter) 

but it just keeps saying connection not found when I go to set it up on the laptop. The can h and can L is also getting low voltage power. 

I go into my runtime values and it says the can is off, so I am completely stumped I feel I have tried everything any help would be much appreciated. Thanks Aidan

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Yeah, the ecu is getting no acknowledge from the lambda device, that usually means wiring issue.  Unplug the CAN plug at the ECU and also unplug the DTM and check continuity from end to end.  Also, pull the orange wedgelock out of the DTM plug and make sure the terminals are still all the way home and with the barb locked under the shoulder.  I have seen some users not push them all the way home before and they back out when you connect the plugs together.  

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Hey I have just checked the continuity from the ecu plug to the dtm for the can H an can L and it is all good. I also check from one side of the dtm plug to the other side an there all getting continuity for all four wires. Starting to loose my mind haha, could it be faulty canbus

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Ok that is good and suggests there is continuity back to the CAN controller in the ECU.  I notice you havent done twisted pair or a terminating resistor which would be more correct for a CAN bus, but still I havent seen that cause one not to be detectable before so we will forget about that for now.   It might be worth a try to swap CAN H with CAN L, although it looks correct in your photos above, photos dont always show the full story so its worth a shot.

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What do you mean I haven’t done a ‘twisted pair or a terminating resistor’ how do you do that I haven’t heard of that before. And I’ll give it ago I did try that a while back but no difference but that’s before I have changed things around. I’ll keep you updated

Unfortunately I just swapped the pins over and still no luck. 

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CAN wiring is meant to be twisted with a 120ohm resistor at both ends of the bus.  The ECU has one built in for the ECU end so you only need to add one at the far end.  However - as I said earlier I doubt this is your problem, it can slow down comms and become more of an issue with a more loaded bus with lots of data on it but a single lambda is not sending much data.

Are you definitely sure that sensor is still getting hot with just ign on, engine not running? 

Qeti4qU.png

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29 minutes ago, Aidan99 said:

it appears that the little black link can lambda unit is not getting hot anymore ? But it is receiving 12v ign power from the relay to it. 

Just the actual sensor should get hot, not so much the black box.  And it will only heat if it is not getting a valid CAN signal from the ECU.  If its getting a CAN signal it knows the engine is not running so wont heat up.  So confirm again - is the sensor getting hot regardless of the CAN plugged in or not?  Or is it only getting hot with the CAN unplugged?  

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