Section 9 (Supplemental Restraint System - Diagnostics): Pre-Check

1. 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.

Fig 1: Identifying Connector Terminals DLC3

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HINT:

If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or LEXUS 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.

Fig 2: Identifying SRS Warning Light Check

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1. Turn the ignition switch to ON, and check that the SRS warning light comes on.
2. 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 blinks, 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. In this case, a short in the SRS warning light circuit is possible. Proceed to v"SRS warning light circuit malfunction" on SRS WARNING LIGHT CIRCUIT MALFUNCTION  .

Fig 3: Identifying Terminals TC And CG Of DLC3

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1. Present troubles codes:

   Output the DTC.

   1. Turn the ignition switch to ON, and wait for approx. 60 seconds.
   2. 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.
2. Past troubles codes:

   Output the DTC.

   1. Using SST, connect terminal TC and CG of the DLC3.

      SST 09843-18040

   2. Turn the ignition switch to ON, and wait for approx. 60 seconds.
   NOTE: Pay attention to the terminal connecting position to avoid a malfunction.
   Fig 4: Identifying Blinking Pattern

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3. Read the DTC.

Read the DTC by counting the blinking times. As an example, the blinking patterns of normal, 11 and 31 are shown in the illustration.

• Normal code indication (w/o past trouble code)

  The light blinks 2 times per seconds.

• 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 inspection on TC TERMINAL CIRCUIT  .

1. Hook up the LEXUS hand-held tester to the DLC3.
2. Read the DTCs by following the prompts on the tester screen.

HINT:

Please refer to the LEXUS hand-held tester operator's manual for further details.

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.

1. Connect the service wire to terminal TC of the DLC3.
2. Ground terminal TC of the DLC3.
3. Turn the ignition switch to the ON position.
4. Within 3 to 10 sec. after DTC is started to be output, release ground from terminal TC of the DLC3.
5. The SRS warning light comes on 2 to 4 sec. later. Within 1 to 5 sec. after that, ground terminal TC of the DLC3.
6. The SRS warning light goes off 2 to 4 sec. after grounding terminal TC. Within 1 to 5 sec. after that, release ground from terminal TC again.
7. The SRS warning light comes on again 2 to 4 sec. later. Within 1 to 5 sec. after that, ground terminal TC of the DLC3 again.
8. The SRS warning light goes off 2 to 4 sec. later. Within 1 sec. after that, normal code is output indicating that DTC deletion is completed.

Fig 5: Connecting Hand-Held Tester

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If DTCs are not cleared, repeat the above procedure until the codes are cleared.

Fig 6: Blinking Pattern

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1. Hook up the LEXUS hand-held tester to the DLC3.
2. Clear the DTCs by following the prompts on the tester screen.

HINT:

Please refer to the LEXUS hand-held tester operation's manual for further details.

Fig 7: Connecting Hand-Held Tester

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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 (Refer to Fig 9).

Fig 8: Communication Diagram Airbag Sensor Assembly

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Fig 9: Identifying Connector Terminals Airbag Sensor Assembly

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