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.

medium speed CAN circuits (W/O) and (P/O), shorted to ground or open
SJB power circuit (T/B) open
SJB ground circuit (B/W) open
DLC D-01
SJB instrument cluster
battery junction box (BJB) fuse 19 (40A)

NO MEDIUM SPEED CONTROLLER AREA NETWORK (CAN) COMMUNICATION - DIAGNOSTIC PROCEDURE

PINPOINT TEST 6		NO MEDIUM SPEED CONTROLLER AREA NETWORK (CAN) COMMUNICATION
STEP	INSPECTION		ACTION
1	CHECK THE SJB GROUND CIRCUIT Key OFF. Disconnect the SJB J-2280a. Measure the resistance between the SJB J-2280a pin 21, circuit (B/W), harness side and ground. Is the resistance less than 5 ohms?	Yes	GO to next step.
1		No	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2	CHECK THE SJB POWER SUPPLY Re-connect the SJB J-2280a. Disconnect the SJB J-2280b. Key ON. Measure the voltage between the SJB J-2280b pin 4, circuit (T/B), harness side and ground. Is the voltage greater than 10 volts?	Yes	GO to next step.
2		No	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
3	CHECK THE MEDIUM SPEED CAN CIRCUITS BETWEEN THE SJB AND THE DLC FOR AN OPEN Key OFF. Disconnect the SJB J-2280a. Measure the resistance between the SJB J-2280a pin 25, circuit (W/O), harness side and the DLC D-01 pin 3, circuit (W/O), harness side; and between the SJB J-2280a pin 26, circuit (P/O), harness side and the DLC D-01 pin 11, circuit (P/O), harness side. Are the resistances less than 5 ohms?	Yes	GO to next step.
3		No	REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
4	CHECK THE MEDIUM SPEED CAN CIRCUITS BETWEEN THE INSTRUMENT CLUSTER AND THE DLC FOR AN OPEN Disconnect the Instrument Cluster 0922-101. Measure the resistance between the instrument cluster 0922-101 pin 14, circuit (W/O), harness side and the DLC D-01 pin 3, circuit (W/O), harness side; and between the instrument cluster 0922-101 pin 15, circuit (P/O), harness side and the DLC D-01 pin 11, circuit (P/O), harness side. Are the resistances less than 5 ohms?	Yes	GO to next step.
4		No	REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
5	CHECK THE MEDIUM SPEED CAN CIRCUITS FOR A SHORT TO GROUND Measure the resistance between the DLC D-01 pin 3, circuit (W/O), harness side and ground; and between the DLC D-01 pin 11, circuit (P/O), harness side and ground. Are the resistances greater than 10,000 ohms?	Yes	GO to next step.
5		No	REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
6	CHECK THE MEDIUM SPEED CAN CIRCUITS FOR A SHORT TO POWER Key ON. Measure the voltage between the DLC D-01 pin 3, circuit (W/O), harness side and ground; and between the DLC D-01 pin 11, circuit (P/O), harness side and ground. Is any voltage indicated?	Yes	REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
6		No	GO to next step.
7	CHECK THE CAN NETWORK WITH A SUBSTITUTED SJB Key OFF. Re-connect the Instrument Cluster 0922-101. INSTALL a known good SJB. Key ON. Enter the following diagnostic mode on the WDS or equivalent Tester: Data Link Diagnostics Test. Does the WDS or equivalent Tester indicate system passed?	Yes	GO to step 9.
7		No	GO to next step.
8	CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all the instrument cluster connectors. Check for: corrosion pushed-out pins Connect all the instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	INSTALL a new instrument cluster. See INSTRUMENT CLUSTER (IC) REPLACEMENT PROCEDURE - WDS . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
8		No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
9	CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion pushed-out pins Connect all the SJB module connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	INSTALL a new SJB. See SMART JUNCTION BOX (SJB) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
9		No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.