LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2001 >> IS 300 >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Remote Keyless Entry Systems >> Symptom Tests >> Remote Transmitter Inoperative
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Remote Transmitter Inoperative

  1. Remove key from ignition switch. Ensure door lock control switch (buzzer switch) is on and all doors are closed and locked. While standing outside vehicle near driver's door, point transmitter toward vehicle. Press door LOCK button, and then UNLOCK button on transmitter for about one second. If doors do not lock and unlock properly, go to next step. If doors lock and unlock properly, system is okay at this time.
  2. Observe transmitter LED while pressing transmitter LOCK and UNLOCK buttons. If transmitter LED illuminates when transmitter LOCK and UNLOCK buttons are pressed, go to step  4. If transmitter LED does not illuminate when transmitter LOCK and UNLOCK buttons are pressed, go to next step.
  3. Replace transmitter battery. Check transmitter functions. If transmitter still does not operate properly, go to next step. If transmitter operates properly with new battery, system is okay.
  4. Remove key from ignition switch. Ensure all doors are closed and locked. Go to next step.
  5. Perform the following within 35 seconds: insert key into ignition switch, and then remove it. Insert key once more. Turn ignition on, and then off one time within 5 seconds. Within 30 seconds, turn ignition on and off 9 additional times. Dome light should come on, indicating successful entry into diagnostic mode. If dome light comes on and system enters diagnostic mode as specified, go to next step. If system does not enter diagnostic mode regardless of dome light operation, go to step  9.
  6. Press LOCK, UNLOCK or TRUNK button on transmitter. Dome light should come on about every .5 second. If dome light operation is as specified, go to next step. If dome light stays on, go to step  11. If dome light does not come on at all, go to step  12.
  7. While standing about 3 feet from vehicle, press any transmitter button for 20 seconds (dome light should light continuously), and then press button again. If dome light operates as specified, other body control systems may be at fault (transmitter and wireless door lock receiver are okay). See BODY CONTROL SYSTEMS - IS300 article. If dome light does not operate as specified, go to next step.
  8. Transmitter or wireless door lock receiver is faulty. Repeat step  7 using a known-good transmitter. Replace original transmitter if necessary. If problem still exists, check wireless door lock receiver. See WIRELESS DOOR LOCK RECEIVER CIRCUIT  under CIRCUIT TESTS. Repair as necessary.
  9. Repeat step  5, ensuring procedures are performed correctly. If dome light operation is normal, but still does not enter diagnostic mode, go to next step. If dome light still does not come on, check dome light. Repair as necessary.
  10. Insert key into ignition switch. Using DVOM, check for continuity between ground and terminal No. 6 (Black/Yellow wire) at body ECU harness connector B6. See WIRING DIAGRAMS . Continuity should be present. If continuity is not present, repair key unlock warning switch or circuit as necessary.
  11. Program transmitter. See PROGRAMMING . Retest system operation.
  12. Repeat step  6 using a known-good transmitter. If transmitter operates, replace original transmitter. If transmitter does not operate, go to next step.
    13. NOTE: The following step checks for wireless door lock signal error. For additional information on retrieving and diagnosing body ECU Diagnostic Trouble Codes (DTC), see MULTIPLEX CONTROL SYSTEMS - IS300 article.
  13. Using jumper wire, connect terminals Tc and E1 of DLC1 together. If DTC B1242/42 is present, repair short circuit in Gray/Blue wire between terminal No. 2 of wireless door lock receiver and terminal No. 2 of body ECU harness connector. See WIRING DIAGRAMS . If DTC B1242/42 is not present, go to next step.
  14. Using DVOM, measure voltage between ground and terminal No. 2 (Gray/Blue wire) at body ECU harness connector when operating transmitter. See WIRING DIAGRAMS . If battery voltage is present, go to next step. If battery voltage is not present, repair open in Gray/Blue wire.
  15. Using DVOM, measure voltage between ground and terminal No. 1 (Red/Black wire) at wireless door lock receiver. Voltage should be 10-14 volts when transmitting. If voltage is as specified, go to next step. If voltage is not as specified, repair open in Red/Black wire.
  16. Using DVOM, measure voltage between ground and terminal No. 1 (White/Black wire) at wireless door lock receiver. See WIRING DIAGRAMS . Battery voltage should be present. If voltage is as specified, go to next step. If voltage is not as specified, repair open circuit in White/Black wire.
  17. Using DVOM, check for continuity between chassis ground and terminal No. 5 (Blue/Yellow wire) at wireless door lock receiver. See WIRING DIAGRAMS . If continuity is present, wireless door lock receiver is faulty. If continuity is not present, repair open or poor connection in Blue/Yellow wire.
scientia non olet · About LEMON Manuals