Initial Inspection and Diagnostic Overview
How to Troubleshoot the SRS
DTC (Diagnostic Trouble Codes)
The self-diagnostic function of the SRS system allows it to locate the causes of system problems and then store this information in memory. For easier troubleshooting, this data can be retrieved via a data link circuit.
- When you turn the ignition switch to ON (II), the SRS indicator should come on. If it goes off after 6 seconds, the system is normal, and is not currently detecting any abnormality.
- If there is an abnormality, the system locates and defines the problem, stores this information in memory, and turns on the SRS indicator. The data remains in memory even if the ignition switch is turned to LOCK (0) or the battery is disconnected.
- The data is stored in memory as a diagnostic trouble code (DTC).
- The "x" at the end of each DTC denotes a numeric character (0 thru 9) or an alpha character (A thru F) that is displayed on the HDS.
- DTCs are either latching or resetting depending on the malfunction. With resetting DTCs, the SRS indicator goes off the next time the ignition switch is turned to ON (II) and the system is normal, but the DTC is still stored. With latching DTCs, the SRS indicator does not turn to LOCK (0) until the malfunction is repaired and the DTC is cleared.
- When you connect the HDS to the data link connector (DLC), you can retrieve a more detailed DTC in the HDS "SRS" menu.
NOTE: Only read DTCs from the SRS menu, not from the SWS menus unless instructed to check SWS DTCs. SWS (ODS unit) DTCs are subcodes of SRS unit DTCs. Only troubleshoot the corresponding SRS DTCs.
- After reading and recording the DTC, proceed with the troubleshooting procedure for that code.
Precautions
- Use only a digital multimeter to check the system. Make sure its output is 10 mA (0.01 A) or less when switched to the smallest value in the ohmmeter range. A tester with a higher output could damage the airbag circuit or cause accidental airbag deployment and possible injury.
- Whenever the ignition switch is in ON (II), or has been turned to LOCK (0) for less than 3 minutes, be careful not to bump the SRS unit; the airbags could accidentally deploy and cause damage or injuries.
- Before you removing the dashboard wire harness, floor wire harness, disconnect the driver's airbag connector, the front passenger's airbag connector, both side airbag connectors, both side curtain airbag connectors, both seat belt tensioner connectors and both seat belt buckle tensioner connectors.
- Make sure the battery is fully charged. If the battery is dead or low, electrical measurement may not be correct.
- Do not touch a tester probe to the terminals in the SRS unit or harness connectors, and do not connect the SRS unit terminals or the sensor terminals with a jumper wire. Use only the backprobe set and the multimeter. Backprobe spring-loaded lock type connectors correctly.
Reading the DTC
1. Make sure the ignition switch is in LOCK (0).
2. Connect the HDS to the data link connector (DLC) (A).
3. Turn the ignition switch to ON (II).
4. Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
5. Use the HDS to check for DTCs.
NOTE: Only read DTCs from the SRS menu, not from the SWS menus unless instructed to check SWS DTCs. SWS (ODS unit) DTCs are subcodes of SRS unit DTCs. Only troubleshoot the corresponding SRS DTCs.
6. Read and record the DTC.
7. Turn the ignition switch to LOCK (0), and wait for 10 seconds.
8. Disconnect the HDS from the DLC.
9. Do the troubleshooting procedure for the DTC.
Clear the DTC Memory With the HDS
NOTE: Make sure the battery is fully charged before you begin.
1. Make sure the ignition switch is in LOCK (0).
2. Connect the HDS to the data link connector (DLC) (A).
3. Turn the ignition switch to ON (II).
4. Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
5. In the SRS MENU of the HDS, select SRS, then DTC to clear DTCs.
6. Turn the ignition switch to LOCK (0), and wait for 10 seconds.
7. Disconnect the HDS from the DLC.
Clear the DTC Memory Using MES Connector Without the HDS
Special Tools Required
- SCS service connector 07PAZ-001010A
NOTE: Make sure the battery is fully charged before you begin.
To clear the DTCs from the SRS unit, use the HDS or the following procedure.
1. Make sure the ignition switch is in LOCK (0).
2. Connect the SCS service connector (A) to the yellow MES 2P connector (B). Do not use a jumper wire.
3. Turn the ignition switch to ON (II).
4. The SRS indicator will come on for about 6 seconds, and then go off. Remove the SCS service connector from the MES connector (2P) within 4 seconds after the indicator goes off.
5. The SRS indicator will come on again. Reconnect the SCS service connector to the MES connector (2P) within 4 seconds after the indicator comes on.
6. When the SRS indicator goes off, remove the SCS service connector from the MES connector (2P) within 4 seconds.
7. The SRS indicator blinks two times, indicating that the memory has been cleared.
8. Turn the ignition switch to LOCK (0), and wait for 10 seconds.
9. Turn the ignition switch to ON (II) again. If the SRS indicator comes on for 6 seconds, and then goes off, the system is OK. If the indicator stays on, troubleshoot the DTC. If there in no DTC, refer to symptom troubleshooting.
Troubleshooting Intermittent Failures
If there was a malfunction, but it does not recur, it will be stored in the memory as an intermittent failure, and the SRS indicator may come on depending on this malfunction detected.
NOTE:
- Check the condition of the battery Testing and Inspection and the IMA system. Initial Inspection and Diagnostic Overview Low battery voltage may cause some intermittent failures.
- A faulty or damaged cable reel can cause intermittent problems related to the driver's airbag inflator DTCs.
After checking the DTC, troubleshoot as follows:
1. Make sure the ignition switch is in LOCK (0).
2. Connect the HDS to the data link connector (DLC).
3. Turn the ignition switch to ON (II).
4. Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
5. In the SRS MENU on the HDS, select SRS, then DTC to clear DTS(s).
6. Read the DTC (see Reading the DTC).
7. Clear the DTC memory (see Clear the DTC).
8. Set the parking brake, then start the engine, and let it idle.
9. The SRS indicator comes on for about 6 seconds and then goes off.
10. Shake the related wire harnesses and the connectors, and look for loose connections, poor pinfits, and poor grounds.
11. Take a test-drive (quick acceleration, quick braking, and cornering), turn the steering wheel fully left and right, and hold it there for 5 to 10 seconds. If the problem recurs, the SRS indicator will come on.
12. If you cannot duplicate the concern, ask the customer about the conditions when it occurred, or ask the customer to demonstrate the concern.
13. If you cannot duplicate the intermittent failure, the system is OK at this time.
Checking Front Passenger's Weight Sensors After a Vehicle Collision
1. Position the front passenger's seat to the rearmost position, adjust the seat-back to the forwardmost position. Do not move it from this position.
2. Drive the vehicle, accelerate to 20 mph (36 km/h), then stop on level ground.
3. Make sure the ignition switch is in LOCK (0).
4. Connect the HDS to the data link connector (DLC) (A).
5. Turn the ignition switch to ON (II).
6. Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
7. From the SRS inspection menu, select Seat Weight Sensor, then Misc test, then SEAT OUTPUT CHK and follow the prompts until the front passenger's weight sensor operation check is complete.
