Did this one a while back on a LLY but had never tested on LBZ/LMM until tonight.
The E35A/B series ECM will accept a single wire square wave pulse signal for vehicle speed just like the LB7/LLY. So you can use any GPS/acceleratometer or other pulse signal generator with square wave pattern in the 0.1khz to 4.5khz range. That range matches the factory setting of 101008 pulses per mile. This signal then becomes usable by the ECM in speed related tables, and is passed along in CANbus data to any gauge setup. I haven't tested on the TCM side cause I didn't have one handy.
The only GPS to pulse unit I've tested so far is the Dakota Digital GPS-50. Sure there are others out there now, but that one has an accelerometer that takes over if GPS signal is lost. So no jumpy readings.
This is a single wire connection. The GM pinout list 2 VSS wires, but only one is used. And NOT the one listed "vehicle speed sensor.."
X2 Pin 45 [VSS HIGH] is the one you want.
X2 Pin 54 [Vehicle Speed Signal] did not work, and might be related to TCM. Needs further testing.
To verify this I used a simple $4 PWM generator from eBay, that's shipped all the way China for free... So expectations weren't very high :rofl: But it works.
The E35A/B series ECM will accept a single wire square wave pulse signal for vehicle speed just like the LB7/LLY. So you can use any GPS/acceleratometer or other pulse signal generator with square wave pattern in the 0.1khz to 4.5khz range. That range matches the factory setting of 101008 pulses per mile. This signal then becomes usable by the ECM in speed related tables, and is passed along in CANbus data to any gauge setup. I haven't tested on the TCM side cause I didn't have one handy.
The only GPS to pulse unit I've tested so far is the Dakota Digital GPS-50. Sure there are others out there now, but that one has an accelerometer that takes over if GPS signal is lost. So no jumpy readings.
This is a single wire connection. The GM pinout list 2 VSS wires, but only one is used. And NOT the one listed "vehicle speed sensor.."
X2 Pin 45 [VSS HIGH] is the one you want.
X2 Pin 54 [Vehicle Speed Signal] did not work, and might be related to TCM. Needs further testing.
To verify this I used a simple $4 PWM generator from eBay, that's shipped all the way China for free... So expectations weren't very high :rofl: But it works.
