How to Troubleshoot the SRS

SRS Indicator

The SRS indicator (A) indicates problems related with SRS function.

If the system is OK, the SRS indicator should come on when you turn the vehicle to the ON mode, and then goes off 6 seconds later. If it does not, there is a problem with the system.

NOTE: If the SRS indicator comes on, and SRS DTCs are not indicated, do the SRS symptom troubleshooting.

How to Troubleshoot Circuits at the SRS Unit Connectors

Special Tools Required

Pin Probe Male 07ZAJ-RDJA110

NOTE:

	Make sure the 12 volt battery is fully charged when doing an electrical test. If the 12 volt battery is not fully charged, the results of the tests may not be accurate.
	To prevent damage to the connector, do not insert test equipment probes, paper clips, or other substitutes. Damaged terminals cause a poor connection and an incorrect measurement.

1.	When diagnosing or troubleshooting at an SRS unit connector (A), use the terminal test port below the terminal you need to check. Gently insert the pin probes of the tester or jumper wire at the terminal test port from the terminal side.

NOTE:

	Do not insert the pin probes of the tester or a jumper wire at the terminal or the SRS short canceller terminal port.
	To prevent damage to the connector terminals, do not insert the test equipment probes, paper clips, or other substitutes as they can damage the terminals. Damaged terminals cause a poor connection and an incorrect measurement.

2.	Connect one side of the patch cord terminals (A) to a commercially available digital multimeter (B), and connect the other side of the terminals (C) to the pin probe male.

Gently contact the pin probe male at the terminal test port from the terminal side. Do not force the tips into the terminals.

NOTE:

	For accurate results, always use the pin probe male.
	To prevent damage to the connector terminals, do not insert test equipment probes, paper clips, or other substitutes. Damaged terminals cause a poor connection and an incorrect measurement.
	Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.

How to Troubleshoot Circuits at the Connectors Except for SRS Unit Connectors, Waterproof SRS Connectors, and SRS Inflator Connectors

Special Tools Required

Back Probe Adapter, 17 mm 07TAZ-001020A

When using electrical test equipment, insert the back probe adapter, 17 mm of the tester into the wire side of the connector (except SRS unit connector, waterproof SRS connector, and SRS inflator connector).

NOTE:

	Make sure the 12 volt battery is fully charged when doing an electrical test. If the 12 volt battery is not fully charged, the results of the tests may not be accurate.
	Do not insert the probe of the tester into the terminal side of the connector, and do not tamper with the connector.
	To prevent damage to the connector, do not insert test equipment probes, paper clips, or other substitutes. Damaged terminals cause a poor connection and an incorrect measurement.
	Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.
	Do not insert the probe forcibly.
	Use specified service connectors in troubleshooting. Using improper tools could cause a diagnostic error due to poor metal-to-metal contact.

Opening the SRS Unit Shorting Connectors for Diagnosis

Special Tools Required

SRS Short Canceller 070AZ-SAA0100

NOTE:

	To prevent damage to the connector cavity, insert an SRS short canceller straight into the cavity from the terminal side.
	Before installing an SRS short canceller, wash it with electrical contact cleaner, then dry it with compressed air.
	Do not use an SRS short canceller if it is damaged.
	Make sure to remove an SRS short canceller before reconnecting the SRS unit connector.
	Some systems store data in memory that is lost when the 12 volt battery is disconnected. Before disconnecting the 12 volt battery, refer to 12 Volt Battery Terminal Disconnection and Reconnection.

When SRS unit connectors A (39P) and B (39P) are disconnected, short circuits are automatically created in the connector to prevent accidental deployment of an airbag or tensioner. The circuit may need to be opened sometimes when diagnosing the system. Insert an SRS short canceller in the specified cavities when necessary to keep the circuit open for diagnosis.

Terminal numbers are shown on the terminal side of the female terminals. Insert the SRS short canceller(s) into the cavities on the terminal side of the connector.

DTC (Diagnostic Trouble Codes)

The self-diagnostic function of the SRS unit allows it to locate the causes of system problems and store this information in memory. For easier troubleshooting, this data can be retrieved with the HDS via the data link circuit.

	When you turn the vehicle to the ON mode, the SRS indicator should come on. If it goes off after 6 seconds, the system is normal, and is not currently detecting any problems.
	If there is a problem, the system locates and defines the problem, stores this information in the memory, and turns on the SRS indicator. The data remains in the memory even if the vehicle is turned to the OFF (LOCK) mode or the 12 volt battery is disconnected.
	The data is stored in memory as a diagnostic trouble code (DTC).
	DTCs are either latching or resetting depending on the malfunction. With resetting DTCs, the SRS indicator goes off the next time the vehicle is turned to the ON mode, and the system is normal, but the DTC is still stored. With latching DTCs, the SRS indicator does not turn off 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.
	After reading and recording the DTC, go to the troubleshooting procedure for that code.

Precautions

	Make sure the 12 volt battery is fully charged. If the 12 volt battery is dead or low, electrical measurements values may not be correct.
	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 vehicle is turned to the ON mode, or the vehicle is turned to the OFF (LOCK) mode for less than 3 minutes, be careful not to bump the SRS unit; the airbags could accidentally deploy and cause damage or injuries.
	Before removing the dashboard wire harness or right side wire harness, disconnect the driver's airbag inflator connector, the front passenger's airbag inflator connector, both side airbag inflator connectors, both side curtain airbag inflator connectors, and both front seat belt tensioner connectors.

How to Read Deployed History

NOTE: The inside of the SRS unit is damaged severely, because severe electric current flows in the SRS unit to deploy the airbags and tensioners. Therefore the SRS unit that has a history to deploy any airbags or tensioners cannot be reused, and must be replaced, with new one.

1.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

2.	Connect the HDS to the data link connector (DLC) (A).

3.	Turn the vehicle to the ON mode.

4.	Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, go to the DLC circuit troubleshooting.

In the SRS MENU of the HDS, select SRS, then select Data List.

Deployed History	State	Detection Item
Deployed History 1	ON	Left front airbag, left side curtain airbag, and/or left front seat belt tensioner deployed
Deployed History 2	ON	Right front airbag, right side curtain airbag, and/or right front seat belt tensioner deployed
Deployed History 3	ON	Left side airbag, left side curtain airbag, and/or left front seat belt tensioner deployed
Deployed History 4	ON	Right side airbag, right side curtain airbag, and/or right front seat belt tensioner deployed
Deployed History 5	ON	Both or only one side curtain airbag and front seat belt tensioner deployed

6.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

How to Read DTCs

NOTE: Make sure the 12 volt battery is fully charged before you begin.

1.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

2.	Connect the HDS to the data link connector (DLC) (A).

3.	Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, go to the DLC circuit troubleshooting.

4.	Use the HDS to check for SRS DTCs.

5.	Read and record the DTC. NOTE: Do not clear the DTC until instructed by the troubleshooting procedure.

6.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

7.	Do the troubleshooting procedure for the DTC.

How to Clear DTCs

NOTE: Make sure the 12 volt battery is fully charged before you begin.

1.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

2.	Connect the HDS to the data link connector (DLC) (A).

3.	Make sure the HDS communicates with the vehicle and the SRS unit. If it does not communicate, go to the DLC circuit troubleshooting.

4.	In the SRS MENU of the HDS, select SRS, then DTC to clear DTCs.

5.	Turn the vehicle to the OFF (LOCK) mode, then wait for 10 seconds.

Troubleshooting Intermittent Failures

If there was a malfunction that sets a DTC, but it does not recur, a DTC will be stored in the memory, and the SRS indicator may come on depending on the malfunction detected.

NOTE:

	Check the condition of the 12 volt battery. 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.	Check for DTCs with the HDS.

2.	Clear the DTCs with the HDS.

3.	Set the parking brake, then start the engine, and let it idle.

4.	The SRS indicator comes on for about 6 seconds and then goes off.

5.	Shake the related wire harnesses and the connectors, and look for loose connections, poor pin fits, and poor grounds.

6.	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.

7.	If you cannot duplicate the concern, ask the customer about the conditions when it occurred, or ask the customer to demonstrate the concern.

8.	If you cannot duplicate the intermittent failure, the system is OK at this time.