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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 182 (Multiplex Communication System) >> Diagnostic Tests >> DTC B1214/14: System Communication Bus Malfunction (+B Short) & DTC B1215/15: System Communication Bus Malfunction (GND Short) >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check the communication circuit inside the ECM. Disconnect the connector E8 of the ECM. See CONNECTOR IDENTIFICATION . Check the DTC. If DTC B1214/14 or DTC B1215 is not output, replace the tilt and telescopic ECU. If the DTC is output, go to the next step.
  2. Check the communication circuit inside the moon roof ECU. Connect the connector E8 of the ECM. Disconnect the connector of the moon roof ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the moon roof ECU. See MOON ROOF article under SUN ROOF/T-TOP/CONVERTIBLE TOP in ACCESSORIES & EQUIPMENT. If the DTC is output, go to the next step.
  3. Check the communication circuit inside the passenger door ECU. Connect the connector of the moon roof ECU. Disconnect the connector of the passenger door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the passenger door ECU. See DRIVER DOOR ECU & FRONT PASSENGER DOOR ECU  under REMOVAL & INSTALLATION. If the DTC is output, go to the next step.
  4. Check the communication circuit inside the rear right door ECU. Connect the connector of the passenger door ECU. Disconnect the connector R13 of the rear right door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the rear right door ECU. If the DTC is output, go to the next step.
  5. Check the communication circuit inside the rear left door ECU. Connect the connector R13 of the rear right door ECU. Disconnect the connector R11 of the rear left door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the rear left door ECU. If the DTC is output, go to the next step.
  6. Check the communication circuit inside power seat ECU. Connect the connector R11 of the rear left door ECU. Disconnect the connector P18 of the power seat ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the power seat ECU. See POWER & HEATED SEATS article under SEATS in ACCESSORIES & EQUIPMENT. If the DTC is output, go to the next step.
  7. Check the communication inside the driver door ECU. Connect the connector P18 of the power seat ECU. Disconnect the connector of the driver door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the driver door ECU. See DRIVER DOOR ECU & FRONT PASSENGER DOOR ECU  under REMOVAL & INSTALLATION. If the DTC is output, go to the next step.
  8. Check the communication circuit inside the A/C and combination meter integrated ECU. Connect the connector of the driver door ECU. Disconnect the connector C14 of A/C and combination meter integrated ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the rear left door ECU. If the DTC is output, go to the next step.
  9. Check the communication circuit inside the center cluster integration panel. Connect the connector C13 of the A/C combination meter integrated ECU. Disconnect the connector I16 of the center cluster integration panel (without navigation system) or I18 of the center cluster integration panel (with navigation system). Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, replace the power seat ECU. See POWER & HEATED SEATS article under SEATS in ACCESSORIES & EQUIPMENT. If the DTC is output, go to the next step.
  10. Check for a short circuit between the center cluster integration panel and body ECU. Disconnect the connector B8 of the body ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between center cluster integration panel and body ECU. If the DTC is output, go to the next step.
  11. Check for a short circuit between the center cluster integration panel and A/C and combination meter integrated ECU. Connect the connector B8 of body ECU. Disconnect the connector C13 of the A/C combination meter integrated ECU. Check the DTC. If the DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the center cluster integration panel and A/C and combination ECU. If the DTC is output, go to the next step.
  12. Check for a short circuit between the A/C and combination meter integrated ECU and the driver door ECU. Connect the connector of the center cluster integration panel. Disconnect the connector of the driver door. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the driver door ECU and A/C and combination meter integrated ECU. If the DTC is output, go to the next step.
  13. Check for a short circuit between the driver door ECU and rear left door ECU. Connect the connector of the center cluster integration panel. Disconnect the connector of the rear left door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the driver door ECU and rear left ECU.
  14. Check for a short circuit between the rear left door ECU and rear right door ECU. Connect the connector of the driver door ECU. Disconnect the connector R40 of the rear right door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the rear left door ECU and rear right door ECU.
  15. Check for a short circuit between the rear right door ECU and passenger door ECU. Connect the connector of the driver door ECU. Disconnect the connector of the passenger door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the rear right door ECU and passenger door ECU. If the DTC is output, go to the next step.
  16. Check for a short circuit between the passenger door ECU and ECM. Connect the connector of the rear right door ECU. Disconnect the connector E8 of the ECM. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the ECM and passenger door ECU. If the DTC is output, go to the next step.
  17. Check for a short circuit between the ECM and body ECU. Connect the connector of the passenger door ECU. Disconnect the connector B5 of the driver door ECU. Check the DTC. If DTC B1214/14 or DTC B1215/15 is not output, repair or replace the wiring harness between the ECM and body ECU. If the DTC is output, replace the body ECU. See INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.
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