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Home >> Mazda >> 2016 >> 3 Sport, 4D Hatchback, Automatic Trans >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> On-Board Diagnostic [Vehicle Control Module - V/C-Module] >> DTC U101C-00; U101D-00; U1A00-88: Radar Sensor Communication Error >> Diagnostic Procedure
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Diagnostic Procedure

Step Inspection Action
1 INSPECT RADAR SENSOR CONNECTOR 
 Yes Replace the malfunctioning part, then go to Step 8.
No Go to the next step.
2 INSPECT VEHICLE CONTROL MODULE (V/C-MODULE) CONNECTOR 
 Yes Replace the malfunctioning part, then go to Step 8.
No Go to the next step.
3 INSPECT RADAR SENSOR CIRCUIT FOR SHORT TO GROUND 
  • Verify that the radar sensor and vehicle control module (V/C-module) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground:
    • Vehicle control module (V/C-module) terminal AB
    • Vehicle control module (V/C-module) terminal AD
NOTE:
  • Inspect for continuity while shaking the wiring harness between the radar sensor and vehicle control module (V/C-module).
  • Is there continuity?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between radar sensor and vehicle control module (V/C-module).
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Repair or replace the malfunctioning part.

If there is no common connector: 
  • Repair or replace the wiring harness which has a short to ground.

Go to Step 8.
No Go to the next step.
4 INSPECT RADAR SENSOR CIRCUIT FOR OPEN CIRCUIT 
  • Verify that the radar sensor and vehicle control module (V/C-module) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Radar sensor terminal D-vehicle control module (V/C-module) AB
    • Radar sensor terminal C-vehicle control module (V/C-module) AD
NOTE:
  • Inspect for continuity while shaking the wiring harness between the radar sensor and vehicle control module (V/C-module).
  • Is there continuity?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between radar sensor and vehicle control module (V/C-module).
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

If there is no common connector: 
  • Repair or replace the wiring harness which has an open circuit.

Go to Step 8.
5 INSPECT RADAR SENSOR CIRCUIT FOR SHORT 
  • Verify that the radar sensor and vehicle control module (V/C-module) connectors are disconnected.
  • Inspect between the following terminals (wiring harness-side) for continuity.
    • Vehicle control module (V/C-module) terminals AB and AD
NOTE:
  • Inspect for continuity while shaking the wiring harness between the radar sensor and vehicle control module (V/C-module).
  • Is there continuity?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between radar sensor and vehicle control module (V/C-module).
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short circuit.
  • Repair or replace the malfunctioning part.

If there is no common connector: 
  • Repair or replace the wiring harness which has a short circuit.

Go to Step 8.
No Go to the next step.
6 INSPECT RADAR SENSOR CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Verify that the radar sensor and vehicle control module (V/C-module) connectors are disconnected.
  • Connect the negative battery cable.

    (Refer to NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)

  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side):
    • Vehicle control module (V/C-module) terminal AB
    • Vehicle control module (V/C-module) terminal AD
NOTE:
  • Measure the voltage while shaking the wiring harness between the radar sensor and vehicle control module (V/C-module).
  • Is the voltage 0 V  ?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between radar sensor and vehicle control module (V/C-module).
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Repair or replace the malfunctioning part.

If there is no common connector: 
  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 8.
7 PERFORM DTC INSPECTION FOR VEHICLE CONTROL MODULE (V/C-MODULE) 
 Yes Replace the radar sensor, then go to the next step.
(Refer to RADAR SENSOR REMOVAL/INSTALLATION [MAZDA RADAR CRUISE CONTROL (MRCC) SYSTEM] .)
No Go to the next step.
8 VERIFY THAT REPAIRS HAVE BEEN COMPLETED 
 Yes Repeat the inspection from Step 1.

Go to the next step.
No Go to the next step.
9 VERIFY THAT NO OTHER DTCs ARE PRESENT 
  • Verify other DTCs displayed.
  • Are any other DTCs output?
 Yes Perform the corresponding DTC inspection.
No DTC troubleshooting completed.
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