barge Posted April 27, 2020 Report Share Posted April 27, 2020 On my WRX104 PnP ECU I use CAN2 to communicate to the ABS, the DCCD and monitoring of such on my ECUmaster dash is all on a 500kbps bus. Last night this network had no issues. The only item I use from all those devices in wheel speeds in the ECU but it's necessary for a bunch of controls. When I started the car this morning I was getting an ABS error light on my dash. No wheel speeds. If I disconnect the Link physically from the network everything else operates properly. As soon as I connect the ECU the network goes inactive/bus heavy. I see no data if i'm connected with my PCAN to that network. I updated my wiring since my skills have gotten a bit better over the last couple years in hopes that it was just a bad connection or something. No change. I checked the connector off the ecu and resistance is ~120ohm as expected. In the realtime monitor under CAN, CAN2 shows all green, no errors. After spending the day on this i'm a bit baffled and frustrated. I'm not sure how anything could just change overnight unless it was a tune download or something in the meantime. I did flash it to the latest revision. It was one revision old and reflashed the tune and no help. LesboRacer EJ20x v3.03.pclr Quote Link to comment Share on other sites More sharing options...
Vaughan Posted April 27, 2020 Report Share Posted April 27, 2020 Does the ECU show any errors for CAN2? Have you got CAN 1 and CAN 2 plugged in the right way around? Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2020 Report Share Posted April 27, 2020 What’s the resistance between can H&L with everything connected? Possibly you have 3 termination resistors if you are connected to a factory bus. Also, as a test could you move the ecu CAN connection to CAN 1? Quote Link to comment Share on other sites More sharing options...
barge Posted April 27, 2020 Author Report Share Posted April 27, 2020 This had been working just fine in the past several months. The overnight nature is a little baffling to me. The status shows no errors on the can. All green. But ecumaster shows the bus inactive when the ECU is connected, PCAN shows busheavy. I did check the resistance and found some issues. However it had been working fine even with the extra terminators. I may have an issue with having too many devices with built in terminators that's going to hurt me. There are 2 factory devices that have a resistor...and then the ECU does as well. Is there a jumper or anything that can disable the ECU resistor? Yes I will swap the canbus networks and try using 1 for the 500kbps. I should have thought of that but it's been a frustrating day hah. I will test that in the morning. As I reply to this I may be able to work around the issue by sending the abs data through the dash and use that as a data buffer... But I'd still like to make sure the CAN2 network is still functional. Quote Link to comment Share on other sites More sharing options...
barge Posted April 27, 2020 Author Report Share Posted April 27, 2020 Another thing I tested... so when I first connected the ABS over a year ago I connected the ABS directly to the ECU on the CAN2. Even when I do this I don't see wheel speeds from the ABS. Quote Link to comment Share on other sites More sharing options...
barge Posted April 27, 2020 Author Report Share Posted April 27, 2020 Did some testing this morning with my PCAN device. CAN2 is neither receiving or transmitting. I'll tear apart the case again and recheck everything. Verified that CAN1 is working fine...data shown in PCANview. I set up my dash stream on CAN2 and no data. I did double check resistance across High/Low on the connector and it's 120ohm at the ECU which would indicate the wiring is good... but like I said i'll verify again. Quote Link to comment Share on other sites More sharing options...
ClintBHP Posted April 27, 2020 Report Share Posted April 27, 2020 It should be 60ohm. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2020 Report Share Posted April 27, 2020 I agree a properly terminated bus should be 50-60ohm, but from the testing you have done it is now sounding more like something has died in the ecu. Please make yourself confident it is then contact tech support if it needs to come back for repair. Quote Link to comment Share on other sites More sharing options...
barge Posted April 28, 2020 Author Report Share Posted April 28, 2020 14 hours ago, Adamw said: I agree a properly terminated bus should be 50-60ohm, but from the testing you have done it is now sounding more like something has died in the ecu. Please make yourself confident it is then contact tech support if it needs to come back for repair. Yes properly terminated should be 60. The only way to maintain that level with these OEM devices is to be able to remove a terimnator somewhere. But regardless it did work even at 30ohm. The 120ohm checks I did were with no connections. Just checking to make sure the terminator is measuring properly at the ecu. Yes I contacted tech support in the US (i'm actually local to US tech support).... however with the Covid restrictions and the track season looking like it's finally going to kick off I've developed a workaround by reading the data via the Dash and then retransmitting back to the Link ECU over the 1mbps bus. This seems to work well in limited testing i've done with it and it will at least get me through until winter when I can do without the car running for the potential repair time. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.