Fuel injection control (-) signal

Courtesy of MAZDA MOTORS CORP.

PCM terminals 

• Fuel Injection No. 1:1DO (+)-body ground (-)
• Fuel Injection No. 2:1DW (+)-body ground (-)
• Fuel Injection No. 3:1EA (+)-body ground (-)
• Fuel Injection No. 4:1DS (+)-body ground (-)

Oscilloscope setting 

• 20 V/DIV (Y), 50 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up