Vehicle Speed Connections To Automatic Transmissions with Electronic Vehicle Speed Source

VEHICLESPEED+ VEHICLESPEEDSIGNAL+

SIGNALSPEEDOMETER

ECM

VEHICLESPEEDSENSOR

VEHICLESPEED+ VEHICLESPEED1 2 C974-PU C973-GN G808-BU G809-GN

36 37 32 33 P1 J1 SPEEDOMETER+ SPEEDOMETERVEHICLE SPEEDIN+ VEHICLE SPEEDIN-

Wiring Diagram 4 - Vehicle Speed Circuit Using Two Single Coil Vehicle Speed Sensors

7.3.1 Option 1 - One Single Coil Speed Sensor

Use one single coil speed sensor, with the ECM Speedometer output supplying the speedometer input signal. Refer to “Wiring Diagram 2 -Vehicle Speed Circuit Using One Single Coil Vehicle Speed Sensor and ECM Speedometer Output for Speedometer” on page 34.

7.3.2 Option 2 - One Single Coil Speed Sensor

Use one single coil speed sensor, with the ECM J1587 Data Link output supplying the speedometer input signal. Refer to “Wiring Diagram 3 -Vehicle Speed Circuit Using One Single Coil Vehicle Speed Sensor and Data Link for Speedometer” on page 34.

7.3.3 Option 3 - Separate Single Coil Speed Sensors

Using two speed sensors, one for the speedometer, and one for the ECM completely isolates the two circuits. Refer to “Wiring Diagram 4 -Vehicle Speed Circuit Using Two Single Coil Vehicle Speed Sensors” on page 35.

7.3.4 Dual Coil Speed Sensor Dual coil magnetic speed sensors are not recommended because of the increased risk of electrical noise

coupling into the engine control vehicle speed circuit. Ground noise from the circuit connected to the speedometer ground will be coupled into the vehicle speed circuit of the engine control degrading system performance.

7.4 Vehicle Speed Connections To Automatic Transmissions with Electronic Vehicle Speed Source

Some electronically controlled transmissions do not have a passive magnetic vehicle speed signal available. For these transmissions follow guidelines indicated below.

SPEEDOMETER SIGNAL+

SIGNALECM

ELECTRONICVEHICLE SPEEDSOURCE

VEHICLESPEED C974-PU C973-GN G808-BU G809-GN

36 37 32 33 P1 J1 SPEEDOMETER+ SPEEDOMETERVEHICLE SPEEDIN+ VEHICLE SPEEDIN-

Wiring Diagram 5 - Vehicle Speed Circuit with Electronic Vehicle Speed Source

Connect the single vehicle speed signal line to the ECM “Vehicle Speed In +” (P1 terminal-32). Leave ECM “Vehicle Speed In -” (P1 terminal-33) unconnected, without a harness connection to this terminal. NOTE: Do NOT connect terminal-33 to ground when using an electronic vehicle speed source.