Barometric Pressure Sensor: Testing and Inspection

Fig. 23 System checker harness terminal identification:

Exc. 1987-88 Accord & Prelude
1. Disconnect wire harness connector from control unit, then connect system checker harness to control unit and wire harness connector.
2. Turn ignition switch on, then connect suitable voltmeter positive probe to terminal C9 of system checker harness and negative probe to terminal C12, Fig. 23. Voltage should be 2.76---2.96 volts at standard atmospheric pressure.
3. If voltage is not as specified, check for open or short circuit between ECU and PA sensor. Replace PA sensor if wires are in satisfactory condition.