I'm trying to wire up an aftermarket speedometer to an LB7 ECM, and I would like to verify what sort of signal a couple of locations put out before I hook up to them. I see two possible locations in the wiring diagrams. One is C2 pin 49 says it goes to the ABS system; the other is C2 pin 50 shows to go to the instrument panel. Does anyone know what sort of signal these put out?
LB7 VSS output
- Thread starter JoshH
- Start date
Straight from GM regarding circuit #1827 to the EBCM:
" 1827 from the ECM to EBCM. This is a digital signal with a typical HZ reading of approximately 25 HZ per one MPH
(example at 10 MPH typical read may be 250 Hz). The ECM is sending out approximately 12 volts and it also toggles it to
ground to create the signal. "
" 1827 from the ECM to EBCM. This is a digital signal with a typical HZ reading of approximately 25 HZ per one MPH
(example at 10 MPH typical read may be 250 Hz). The ECM is sending out approximately 12 volts and it also toggles it to
ground to create the signal. "
The ABS signal is a 128,000 pulse per mile signal, the instrument cluster signal is a 4,000 pulse per mile standard 12 volt pulled to ground signal. Any aftermarket speedo set to 4K PPM will work off of it. The ABS signal is best left to the ABS only due to it being so many pulses per mile.