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Code 12

WARNING: This page is about a different car, the 1995 Lexus SC 400 and 1995 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: During testing, if codes other than Code 12 are displayed, disregard them.
  1. Disconnect negative battery cable. Wait at least 90 seconds. Remove steering wheel pad. See STEERING WHEEL PAD & SPIRAL CABLE  under REMOVAL & INSTALLATION. Disconnect passenger-side air bag connector, accessible through finish plate inside glove box. See Figure.
  2. Disconnect center air bag sensor connector. At center air bag sensor connector (harness side), measure resistance between terminals 2 (+SR) and 1 (-SR) and terminals 1 (+SL) and 2 (-SL). See Figure. If resistance is not 755-885 ohms, go to CODE 15.
  3. If resistance is 755-885 ohms, reconnect negative battery cable. Turn ignition switch to ON position. At center air bag sensor connector (harness side), measure voltage between ground and terminals 2 (+SR) or 1 (+SL). If one or more volts is present, replace harness between center air bag sensor and front air bag sensor.
  4. If less than one volt is present, measure voltage between body ground and each terminal of spiral cable upper connector (spiral cable side of connector). If less than one volt is present, go to next step. If one or more volt is present, go to step 13).
  5. Measure voltage between body ground and each terminal of passenger-side air bag connector (harness side). If less than one volt is present, go to next step. If one or more volts is present, go to step 9).
  6. Turn ignition switch to LOCK position. Disconnect negative battery cable. Reconnect center air bag sensor connector. Connect jumper wire between terminals of spiral cable upper connector and passenger-side air bag connector (harness side of each connector). Reconnect negative battery cable. Wait at least 2 seconds.
  7. Turn ignition switch to ACC or ON position. Wait at least 20 seconds. Clear codes. See CLEARING CODES  under SELF-DIAGNOSTIC SYSTEM. Turn ignition switch to LOCK position. Wait at least 20 seconds. Turn ignition switch to ACC or ON position. Wait at least 20 seconds.
  8. Connect jumper wire between terminals 7 (Tc) and 5 (E1) of DLC. See Figure. If Code 12 is not displayed, go to next step. If Code 12 is displayed, replace center air bag sensor.
  9. Turn ignition switch to LOCK position. Disconnect negative battery cable. Wait at least 90 seconds. Reconnect spiral cable upper connector (steering wheel pad). Reconnect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ACC or ON position. Wait at least 20 seconds.
  10. Clear codes. See CLEARING CODES  under SELF-DIAGNOSTIC SYSTEM. Turn ignition switch to LOCK position. Wait at least 20 seconds. Turn ignition switch to ACC or ON position. Wait at least 20 seconds. Connect jumper wire between terminals 7 (Tc) and 5 (E1) of DLC. See Figure. If Code 12 is displayed, replace steering wheel pad.
  11. If Code 12 is not displayed, turn ignition switch to LOCK position. Disconnect negative battery cable. Wait at least 90 seconds. Reconnect passenger-side air bag connector. Disconnect spiral cable upper connector (steering wheel pad). Reconnect negative battery cable. Wait at least 2 seconds.
  12. Turn ignition switch to ACC or ON position. Wait at least 20 seconds. Clear codes. See CLEARING CODES  under SELF-DIAGNOSTIC SYSTEM. Turn ignition switch to LOCK position. Wait at least 20 seconds. Turn ignition switch to ACC or ON position. Wait at least 20 seconds. Connect jumper wire between terminals 7 (Tc) and 5 (E1) of DLC. See Figure. If Code 12 is displayed, replace center air bag sensor. If Code 12 is not displayed, go to next step.
  13. Turn ignition switch to LOCK position. Disconnect spiral cable lower connector. Turn ignition switch to ON position. Measure voltage between body ground and each terminal of spiral cable upper connector (spiral cable side of connector). If one or more volts is present, replace spiral cable. If less than one volt is present, replace harness between spiral cable and center air bag sensor.
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