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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 476 (On-Board Diagnostic (Immobilizer System)) >> DTC B1681/P1260: No Detected Communication With The Coil >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.
DTC B1681/P1260 DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 INSPECT COIL POWER SUPPLY SYSTEM 
  • Disconnect the coil connector.
  • Turn the ignition switch to the ON position.
  • Measure the voltage at coil connector terminal D.
    • Is the voltage 8 V or more? 
 Yes Go to the next step.
No Repair the wiring harness.
2 INSPECT WIRING HARNESS BETWEEN COIL AND GROUND 
  • Turn the ignition switch to the LOCK position.
  • Inspect the wiring harness between coil connector terminal C and ground for the following:
    • Short to power supply
    • Open circuit
  • Is the wiring harness normal?
 Yes Go to the next step.
No Repair the wiring harness.
3 INSPECT COIL INPUT SIGNAL CIRCUIT 
  • Connect the coil connector.
  • Turn the ignition switch to the ON position.
  • Measure the voltage at coil connector terminal B.
    • Is the voltage 8 V or more? 
 Yes Go to Step 7.
No Go to the next step.
4 INSPECT COIL INPUT SIGNAL CIRCUIT 
  • Turn the ignition switch to the LOCK position.
  • Disconnect the keyless control module connector.
  • Turn the ignition switch to the ON position.
  • Measure the voltage at keyless control module connector terminal 3E.
    • Is the voltage 8 V or more? 
 Yes Replace the keyless control module and perform procedures for when replacing the keyless control module only.
(See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION .)
(See IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING .)
No Go to the next step.
5 INSPECT COMMUNICATION CIRCUIT (INPUT) FOR CONTINUITY 
  • Turn the ignition switch to the LOCK position.
  • Is there continuity between coil connector terminal B and keyless control module connector terminal 3E?
 Yes Go to the next step.
No Repair the wiring harness.
6 INSPECT COIL INPUT SIGNAL CIRCUIT 
  • Measure the resistance between coil connector terminal B and ground.
    • Is the resistance 10 kilohms or more? 
 Yes Replace the coil.
(See COIL REMOVAL/INSTALLATION .)
No Repair the wiring harness.
7 INSPECT COIL OUTPUT SIGNAL CIRCUIT
  • Connect the coil connector and the keyless control module connector.
  • Turn the ignition switch to the ON position.
  • Measure the voltage at coil connector terminal A.
    • Is the voltage 8 V or more? 
 Yes Replace the coil.
(See COIL REMOVAL/INSTALLATION .)
No Go to the next step.
8 INSPECT COIL OUTPUT SIGNAL CIRCUIT 
  • Turn the ignition switch to the LOCK position.
  • Disconnect the coil connector.
  • Turn the ignition switch to the ON position.
  • Measure the voltage at coil connector terminal A.
    • Is the voltage 8 V or more? 
 Yes Replace the coil.
(See COIL REMOVAL/INSTALLATION .)
No Go to the next step.
9 INSPECT COMMUNICATION CIRCUIT (OUTPUT) FOR CONTINUITY 
  • Turn the ignition switch to the LOCK position.
  • Disconnect the keyless control module connector.
  • Is there continuity between coil connector terminal A and keyless control module connector terminal 3F?
 Yes Repair the wiring harness.
No Go to the next step.
10 INSPECT COIL OUTPUT SIGNAL CIRCUIT 
  • Measure the resistance between keyless control module connector terminal 3F and ground.
    • Is the resistance 10 kilohms or more? 
 Yes Replace the keyless control module and perform procedures for when replacing the keyless control module only.
(See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION .)
(See IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING .)
No Repair the wiring harness.
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