Circuit Open/Short Inspection

Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION .)
Connect the SST (104 Pin Breakout Box) the PCM disconnected.
Tighten the connector attaching bolt.
Tightening torque 3.0-5.4 N.m {30-56 kgf.cm, 27-48 in.lbf}

Fig 1: Connecting 104 Pin Breakout Box
Courtesy of MAZDA MOTORS CORP.
Inspect the following wiring harness for open or short circuit (Continuity check).
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
  - EGR valve terminal E (harness-side) and 104 pin breakout box terminal 98
  - EGR valve terminal A (harness-side) and 104 pin breakout box terminal 99
  - EGR valve terminal B (harness-side) and 104 pin breakout box terminal 72
  - EGR valve terminal F (harness-side) and 104 pin breakout box terminal 73
  - EGR valve terminal C or D (harness-side) and main relay terminal D (harness-side)
  Fig 2: Identifying EGR Valve Connector And Main Relay
  Courtesy of MAZDA MOTORS CORP.
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
  - EGR valve terminal E (harness-side) and GND
  - EGR valve terminal A (harness-side) and GND
  - EGR valve terminal B (harness-side) and GND
  - EGR valve terminal F (harness-side) and GND
  - EGR valve terminal C or D (harness-side) and power supply
Remove the EGR valve, and inspect for any damage or clogging.
- If there is no damage or no clogging, replace the EGR valve.