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DTC B2470, Daytime Running Lights Fault: Testing

  1. If BCM system check was performed, go to next step. If BCM system check was not performed, go to BCM SYSTEM CHECK  .
  2. Connect scan tool. Select DAYTIME RUNNING LIGHTS from light test menu in Special Functions. While observing scan tool, press on and off buttons on scan tool several times. If status changes and DRL operates with commanded state, go to next step. If status does not change or DRL does not operate with commanded state, go to step 4).
  3. Check for poor connection at BCM 32-pin, connector C2, terminal C05 (Brown/Purple wire). Check all BCM power and ground circuits. See WIRING DIAGRAM  . Ensure all connectors and components are connected. Using scan tool, clear codes. Check for codes. If DTC B2470 is set, go to step 12). If DTC B2470 is not set, go to BCM SYSTEM CHECK  .
  4. Disconnect BCM 32-pin C2 connector. Check voltage at BCM connector C2, terminal C05 (Brown/Purple wire). If battery voltage exists, go to step 3). If battery voltage does not exist, go to next step.
  5. Remove DRL relay. See Figure . Using DVOM, check resistance between DRL relay terminal No. 1 (Brown/Purple wire) at relay box and BCM connector C2, terminal C05 (Brown/Purple wire). If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, go to step 7).
  6. Move DVOM lead from DRL relay terminal No. 1 (Brown/Purple wire) at relay box to ground. If resistance is infinite, go to step 8). If resistance is not infinite, go to step 9).
  7. Repair open in Brown/Purple wire between DRL relay and BCM. Perform BCM SYSTEM CHECK  .
  8. Leaving DVOM connected as specified in step 6), switch DVOM to DC volts scale. Record voltage reading. Turn ignition switch to ON position. Record voltage reading. If both voltage readings are less than one volt, go to step 10). If both voltage readings are not less than one volt, go to step 11).
  9. Repair short to ground in Brown/Purple wire between DRL relay and BCM. Perform BCM SYSTEM CHECK  .
  10. Replace DRL relay. Reinstall all connectors and components. Using scan tool, clear codes. Check for codes. If DTC B2470 is not set, go to BCM SYSTEM CHECK  . If DTC B2470 is set, go to step 12).
  11. Repair short to battery in Brown/Purple wire between DRL relay and BCM. Perform BCM SYSTEM CHECK  .
  12. Replace BCM. Perform BCM SYSTEM CHECK  .
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