Possible Causes

WARNING: This page is about a different car, the 2005 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.

DLC D-01
diagnostic tool
circuit (O/LG) open
circuit (B/LB) open
circuit (B) open

NO MODULE/NETWORK COMMUNICATION - NO POWER TO DIAGNOSTIC TOOL - DIAGNOSTIC PROCEDURE

PINPOINT TEST 8		NO MODULE/NETWORK COMMUNICATION - NO POWER TO THE DIAGNOSTIC TOOL
STEP	INSPECTION		ACTION
1	CHECK THE DIAGNOSTIC TOOL CONNECTOR Inspect the WDS or equivalent Tester pins for damage. Are the pins OK?	Yes	GO to next step.
1		No	REPAIR the WDS or equivalent Tester connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2	CHECK THE DLC D-01 FOR DAMAGE Key OFF. Inspect the DLC D-01 pins for damage. Are the pins OK?	Yes	GO to next step.
2		No	REPAIR the DLC D-01. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
3	CHECK THE VOLTAGE TO THE DIAGNOSTIC TOOL Key ON. Measure the voltage between the DLC D-01 pin 16, circuit (O/LG), harness side and ground. Is the voltage greater than 10 volts?	Yes	GO to next step.
3		No	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
4	CHECK THE DLC GROUND CIRCUITS Key OFF. Measure the resistance between the DLC D-01 pin 4, circuit (B), harness side and ground; and between the DLC D-01 pin 5, circuit (B/W), harness side and ground. Are the resistances less than 5 ohms?	Yes	REPAIR the WDS or equivalent Tester. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
4		No	REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
Courtesy of MAZDA MOTORS CORP.