VSS 4k signal from Dkota Digital Box show no speed at ECU
Hello,
I'm stuck with a VSS problem. I have a LS3 w/T56 Mag and E38. Currently I have the VSS going from the T56 to the DD box and everything reads correctly on the gauges. I am now trying to use the speed output on the Dakota Digital box(which can do 2k or 4k) to the ECM at pin 71. I've tried all kinds of different combinations of settings but everything still reads 0mph. Can the e38 handle a 4k signal or does it need a 128k?
so, short version of a silly story from me about my similar situation. ls7 t56 magnum with DD vhx guages. i was too focused on using hp tuners to calibrate for the guages that i forgot that i had to actually set the speedometer with the switch that is supplied with the guages. once that was done i could adjust and still need to verify if my speedo is correct. the switch supplied with the guages will allow for 2k or 4k ppm.
Last edited by LS ROB; 12-27-2021 at 10:20 PM.
Reason: corrected ppm
Does the ECM not read the VSS if you wire it direct and leave the DD box out of the equation?
Did the original Camaro/manual trans app use a trans-mounted VSS or get a simulated/composite VSS signal over CAN from wheel speed sensors? Sorry, I don't have service manuals past 2009. If you're working on this you should have them though. Parts catalog does show a speed sensor for manual trans but you know how that goes.
Hello,
From what I see in the service manual it gets the signal from the trans. I had heard conflicting info on that and that's why I tried the DD unit. Both the VSS and the DD box will send the correct signal for the speedo( so I'm thinking both the DD box and the VSS are working) but I get nothing to the ECM.
I'd appreciate anything to try because I'm officially stuck.
So if you have a known-functional VSS reading a real toothed wheel on the output shaft and able to send a real VSS signal over the wiring, and it's wired up to match a 2013 Camaro manual trans diagram, and it's running a 2013 Camaro manual trans OS, and the tune file is set up to match a 2013 Camaro manual trans speedo settings, and it still doesn't work, isn't there only one component left that's an unknown? The ECM itself?
In the course of all this, have you tried a different ECM yet? I seem to remember that way back you were fighting this with an auto trans ECM of some sort, maybe?
And, have you tried it with all settings in the Speedo tab matching the stock 2013 settings?
Couple of observations about your file. All your OS and segment IDs are correct for the VIN per TIS, but I have a 2013 Camaro LS3/M6 file from the repository that has the same OS but the Speedo and Engine Operation segments are different. Wonder if it might be time to try swapping those in and see what happens. 2013 Camaro SS LS3 M6 1491443737.hpt
You are correct, I started all of this with an auto ECM and replaced it with one from a manual. I think I've tried every combo in the speedo tab. I think your right that it comes down to the ECM in some way. Good catch on the OS, is that a dealer only thing to make that change?
For right now don't worry about the pulses per/revs per crap, just try to get it to read some kind of signal.
I don't know what's different in the two Speedo segments, the majority of the code isn't anything you can see in the editor, it's all comms and configuration stuff that happens in the background.
I was able to do the segment swap but unfortunately that didn't solve the issue. Is there any way to use a multimeter or something to check the signal in the wire to the ECM?
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