Supplemental Restraint System - Diagnostics: Overview Lexus GS III

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1. DIAGNOSIS SYSTEM Check the DLC3. HINT: The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format. TERMINALS VOLTAGE Terminal No. Connection/Voltage or Resistance Condition 7 Bus + Line/Pulse generation During Transmission 4 Chassis Ground <=> Body Ground/1 ohm or less Always 16 Battery Positive <=> Body Ground/9 -14 V Always HINT: If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or hand-held tester to the DLC3, turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool side. If communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle. If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.
2. SRS WARNING LIGHT CHECK Turn the ignition switch to ON, and check that the SRS warning light comes on. Check that the SRS warning light goes out after approx. 6 seconds. HINT: When the ignition switch is at ON and the SRS warning light remains on or flashes, the airbag sensor assembly has detected a malfunction code. If, after approx. 6 seconds have elapsed, the SRS warning light sometimes comes on even when the ignition switch is OFF, a short in the SRS warning light circuit is possible. Proceed to " «SRS WARNING LIGHT CIRCUIT MALFUNCTION»(ref-229355-S15452396272006041400000) ".
3. DTC CHECK (Using diagnosis check wire) Present troubles codes: Output the DTC. Turn the ignition switch to ON, and wait for approx. 60 seconds. Using SST, connect terminal TC and CG of the DLC3. SST 09843-18040 NOTE: Pay attention to the terminal connecting position to avoid a malfunction. Past troubles codes: Output the DTC. Using service wire, connect terminal TC and CG of the DLC3. SST 09843-18040 Turn the ignition switch to ON, and wait for approx. 60 seconds. NOTE: Pay attention to the terminal connecting position to avoid a malfunction. Read the DTC. Read the 2-digit DTC as indicated by the number of times the SRS warning light blinks. As an example, the blinking patterns, normal, 11 and 31 are shown in the illustration. Normal code indication (w/o past trouble code) The light will blink 2 times per second. Normal code indication (w/past trouble code) When the past troubles code is stored in the airbag sensor assembly, the light blinks only ones a second. Malfunction code indication The first blinking indicates the first DTC. Second blinking occurs after 1.5-second of pausing. If there are 2 or more codes, there will be a 2.5-second pause between each code. After all the codes are shown, there will be a 4.0-second pausing, and they will all be repeated. HINT: If 2 or more malfunctions are found, the indication starts from the smaller numbered code. If the light does not blink or comes out at all, or if DTCs are indicated without a connection of the terminals, proceed to the " «TC TERMINAL CIRCUIT»(ref-229355-S34493964332006041400000) ".
4. DTC CHECK (Using LEXUS hand-held tester) Hook up the LEXUS hand-held tester to the DLC3. Read the DTCs by following the prompts on the tester screen. HINT: Refer to the LEXUS hand-held tester operator's manual for further details.
5. DTC CLEARANCE (Not using service wire) When the ignition switch is turned off, the diagnostic trouble code is cleared. HINT: Depending on the DTC, the code might not be cleared by turning the ignition switch OFF. In this case, proceed to the next step.
6. DTC CLEARANCE (Using service wire) Using SST, connect terminal TC and CG. SST 09843-18040 Disconnect terminal TC of DLC3 within 10 seconds after the DTCs appear, and check if the warning light come on within 3.0 seconds. Within 2.0 seconds to 4.0 seconds after the SRS warning light come on, re-connect the terminals TC and CG of DLC3. SRS warning light goes off 3.0 seconds after re-connecting the terminal TC and CG. Then disconnect the terminal TC of DLC3 within 2.0 to 4.0 seconds after the SRS warning light goes off. Warning light comes on within 3.0 seconds after re-disconnecting the terminal TC and CG. Within 2.0 seconds to 4.0 seconds after the SRS warning light come on, re-connect the terminals TC and CG of DLC3. SRS warning light goes off 3 seconds after re-connecting the terminal TC and CG. Normal code appears 1.0 second after the SRS warning light goes off. If DTCs are not cleared, repeat the above procedure until the codes are cleared.
7. DTC CLEARANCE (Using LEXUS hand-held tester) Hook up the LEXUS hand-held tester to the DLC3. Clear the DTCs by following the prompts on the tester screen. HINT: Refer to the LEXUS hand-held tester operation's manual for further details.
8. RELEASE METHOD OF AIRBAG ACTIVATION PREVENTION MECHANISM An airbag activation prevention mechanism is built into the connector for the squib circuit of the SRS. As explained in the troubleshooting later, insert a paper with the same thickness as the male terminal between the terminal and the short spring to release it ( (Scheme 10)& (Scheme 11) ). CAUTION: Never release the airbag activation prevention mechanism on the squib connector. NOTE: Do not release the airbag activation prevention mechanism unless specifically directed by the troubleshooting procedure. To prevent the terminal and the short spring to be damaged, always use a paper with the same thickness as the male terminals.

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See also:
• COMBINATION METER