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