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Home >> Mazda >> 2017 >> CX-5 Grand Select, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 86 (On-Board Diagnostic - Advanced Keyless Entry System) >> DTC B13C3-29: Communication Error With LF Control Unit >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.
Step Inspection Action
1 INSPECT LF CONTROL UNIT CONNECTOR CONDITION 
Yes Go to the next step.
No Repair or replace the connector, then go to Step 6.
2 INSPECT START STOP UNIT CONNECTOR CONDITION 
  • Disconnect the start stop unit connector.
  • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.
  • Is the connector normal?
Yes Go to the next step.
No Repair or replace the connector, then go to Step 6.
3 INSPECT LF CONTROL UNIT CIRCUIT FOR SHORT TO GROUND 
  • Verify that the start stop unit and LF control unit connectors are disconnected.
  • Inspect for continuity between LF control unit terminal I and body ground.
  • Is there continuity?
Yes Repair or replace the wiring harness which is shorted to ground, then go to Step 6.
No Go to the next step.
4 INSPECT LF CONTROL UNIT CIRCUIT FOR OPEN CIRCUIT 
  • Verify that the start stop unit and LF control unit connectors are disconnected.
  • Inspect the wiring harness for continuity between start stop unit terminal 2F (vehicle wiring harness side) and LF control unit terminal I.
  • Is there continuity?
Yes Go to the next step.
No Repair or replace the wiring harness which has an open circuit, then go to Step 6.
5 INSPECT LF CONTROL UNIT 
Yes Go to the next step.
No Replace the LF control unit, then go to the next step.
(See LF CONTROL UNIT REMOVAL/INSTALLATION .)
6 VERIFY THAT REPAIRS HAVE BEEN COMPLETED 
Yes Repeat the inspection from Step 1.
No Go to the next step.
7 VERIFY IF OTHER DTCs DISPLAYED 
  • Are any other DTCs displayed?
Yes Repair the malfunctioning part according to the applicable DTC troubleshooting.
(See DTC TABLE [ADVANCED KEYLESS ENTRY SYSTEM] .)
No DTC troubleshooting completed.