DTC Troubleshooting: U3000-49 (SRS Unit: KA/KC models)

DTC Troubleshooting: U3000-49

DTC U3000-49: Internal Failure of the SRS Unit

NOTE:

	Before doing this troubleshooting procedure, find out if the vehicle was in a collision. If so, verify that all the required components were replaced with new components of the correct part number and were properly installed.
	Before doing this troubleshooting procedure, review SRS Precautions and Procedures, General Troubleshooting Information, and 12 Volt Battery Terminal Disconnection and Reconnection.

DTC Description	DTC
U3000-49 Internal failure of the SRS unit

Problem verification:

Problem verification

?1.	Clear the DTCs with the HDS.

?2.	Turn the vehicle to the ON mode, then wait for 10 seconds.

?3.

Check for DTCs with the HDS.

DTC Description	DTC
U3000-49 Internal failure of the SRS unit

Is DTC U3000-49 indicated?


	YES

The failure is duplicated. Go to step 2.


	NO

Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures. If another DTC is indicated, troubleshoot the DTC.?

Shorted wire check (SWS?/PWR SWS lines to power) :

Shorted wire check (SWS?/PWR SWS lines to power)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Disconnect the negative cable from the 12 volt battery, then wait at least 3 minutes.

?3.

Disconnect the following connectors.

SRS unit connector B (39P)

Front passenger's weight sensor (front inner side) 3P connector (on the front passenger's seat wire harness)

Front passenger's weight sensor (rear inner side) 3P connector (on the front passenger's seat wire harness)

?4.	Reconnect the negative cable to the 12 volt battery.

?5.	Turn the vehicle to the ON mode.

?6.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
Test condition	SRS unit connector B (39P): disconnected
	Front passenger's weight sensor (front inner side) 3P connector (on the front passenger's seat wire harness): disconnected
	Front passenger's weight sensor (rear inner side) 3P connector (on the front passenger's seat wire harness): disconnected
Test point 1	SRS unit connector B (39P) No. 26
Test point 2	Body ground

Is there 0.2 V or less?


	YES

The SWS?/PWR SWS wires are not shorted to power. Go to step 3.


	NO

Short to power in the floor wire harness or the front passenger's seat wire harness; replace the faulty harness, then clear the DTC.?

Shorted wire check (SWS?/PWR SWS lines) :

Shorted wire check (SWS?/PWR SWS lines)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Disconnect the negative cable from the 12 volt battery, then wait at least 3 minutes.

?3.

Measure the resistance between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	SRS unit connector B (39P): disconnected
	Front passenger's weight sensor (front inner side) 3P connector (on the front passenger's seat wire harness): disconnected
	Front passenger's weight sensor (rear inner side) 3P connector (on the front passenger's seat wire harness): disconnected
Test point 1	SRS unit connector B (39P) No. 26
Test point 2	Body ground

Is there an open circuit, or at least 1 M??


	YES

The SWS?/PWR SWS wires are not shorted. Go to step 4.


	NO

Short to ground in the floor wire harness or the front passenger's seat wire harness; replace the faulty harness, then clear the DTC.?

Shorted wire check (SWS?/PWR SWS lines to SWS?/GND SWS lines) :

Shorted wire check (SWS?/PWR SWS lines to SWS?/GND SWS lines)

?1.

Measure the resistance between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	SRS unit connector B (39P): disconnected
	Front passenger's weight sensor (front inner side) 3P connector (on the front passenger's seat wire harness): disconnected
	Front passenger's weight sensor (rear inner side) 3P connector (on the front passenger's seat wire harness): disconnected
Test point 1	SRS unit connector B (39P) No. 26
Test point 2	SRS unit connector B (39P) No. 28

Is there an open circuit, or at least 1 M??


	YES

The SWS?/PWR SWS wires and SWS?/GND SWS wires are OK. Go to step 5.


	NO

Short to another wire in the floor wire harness or the front passenger's seat wire harness; replace the faulty harness, then clear the DTC.?

Front passenger's weight sensor check:

Front passenger's weight sensor check

?1.	Substitute a known-good front passenger's weight sensors as an assembly.

?2.

Reconnect the following connectors.

SRS unit connector B (39P)

Front passenger's weight sensor (front inner side) 3P connector (on the front passenger's seat wire harness)

Front passenger's weight sensor (rear inner side) 3P connector (on the front passenger's seat wire harness)

?3.	Reconnect the negative cable to the 12 volt battery.

?4.	Clear the DTCs with the HDS.

?5.	Turn the vehicle to the ON mode, then wait for 10 seconds.

?6.

Check for DTCs with the HDS.

DTC Description	DTC
U3000-49 Internal failure of the SRS unit

Is DTC U3000-49 indicated?


	YES

The front passenger's weight sensor is OK. Faulty SRS unit or poor connection at SRS unit connector B (39P) and the SRS unit. Check the connection; if the connection is OK, check for any authorized service information related to the DTCs or symptoms you are troubleshooting or replace the SRS unit.?


	NO

Faulty front passenger's weight sensor. Replace the front passenger's weight sensors as an assembly.?