Fuel injection control (-) signal

Courtesy of MAZDA MOTORS CORP.

PCM terminals 

• Fuel Injection No. 1: 1DH(+)-body ground(-)
• Fuel Injection No. 2: 1CZ(+)-body ground(-)
• Fuel Injection No. 3: 1CV(+)-body ground(-)
• Fuel Injection No. 4: 1DD(+)-body ground(-)

Oscilloscope setting 

• 10 V/DIV (Y), 5 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up