Denso SRS Unit

Control System DTCs

SRS DTC Troubleshooting: 43-1x, 45-1x - DENSO SRS unit

DTC 43-1x ("x" can be 0 thru 9 or A thru F) : No Signal From the Left Side Impact Sensor (first) (DENSO SRS unit)
DTC 45-1x ("x" can be 0 thru 9 or A thru F) : No Signal From the Left Side Impact Sensor (second) (DENSO 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 that they were properly installed Service and Repair.
* Before doing this troubleshooting procedure, review SRS Precautions and Procedures Service and Repair, General Troubleshooting Information Reading and Clearing Diagnostic Trouble Codes, and Battery Terminal Disconnection and Reconnection Procedures.
* Before replacing the SRS unit, check the SRS unit software version with the HDS. If the software version is not the latest, update the SRS unit software Programming and Relearning, and retest.

1. System check 1:

System check 1
-1. Turn the ignition switch to LOCK (0).

-2. Connect the HDS to the data link connector (DLC) Reading and Clearing Diagnostic Trouble Codes.

-3. Turn the ignition switch to ON (II).

-4. From the HDS Main Menu, select SRS, then Data List. Read "ECU MAKER" displayed on the HDS.

Is DENSO indicated?
-YES- Go to step 2.
-NO- Troubleshoot appropriate DTC.
CONTINENTAL SRS unit :
* DTC 43-1x Continental SRS Unit
* DTC 45-1x Continental SRS Unit
TRW SRS unit :
* DTC 43-1x TRW SRS Unit
* DTC 45-1x TRW SRS Unit

2. DTC check (45-xx (except 45-11)):

DTC check (45-xx (except 45-11))
-1. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-2. Turn the ignition switch to ON (II), then wait for 10 seconds.

-3. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 45-xx (except 45-11) indicated?
-YES- Faulty left side impact sensor (second); replace the left side impact sensor (second) Side Impact Sensor (Second) Removal and Installation (4-door), then clear the DTC.
-NO- Go to step 3.

3. DTC check (43-xx (except 43-11)):

DTC check (43-xx (except 43-11))
-1. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 43-xx (except 43-11) indicated?
-YES- Faulty left side impact sensor (first); replace the left side impact sensor (first) Side Impact Sensor (First) Removal and Installation (4-door), then clear the DTC.
-NO- Go to step 4.

4. DTC check (45-11):

DTC check (45-11)
-1. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 45-11 indicated?
-YES- Go to step 6.
-NO- Go to step 5.

5. DTC check (43-11):

DTC check (43-11)
-1. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 43-11 indicated?
-YES- Go to step 14.
-NO- Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures Reading and Clearing Diagnostic Trouble Codes. If another DTC is indicated, troubleshoot the DTC.

6. Connector and harness visual check:

Connector and harness visual check
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the negative cable from the battery, then wait at least 3 minutes.

-3. Check the following connectors and harness.





Are the connectors and harness OK?
-YES- Go to step 8.
-NO- Go to step 7.

7. System check 2:

System check 2
-1. Repair the poor connector connections or replace the harness whichever was the cause of the problem in step 6.

-2. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-3. Turn the ignition switch to ON (II), then wait for 10 seconds.

-4. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 45-11 indicated?
-YES- Turn the ignition switch to LOCK (0), then go to step 8.
-NO- Troubleshooting is complete.

8. Left side impact sensor (second) substituting:

Left side impact sensor (second) substituting
-1. Substitute a known-good left side impact sensor (second) Side Impact Sensor (Second) Removal and Installation (4-door).

-2. Reconnect the negative cable to the battery.

-3. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-4. Turn the ignition switch to ON (II), then wait for 10 seconds.

-5. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 45-11 indicated?
-YES- Go to step 9.
-NO- Faulty original left side impact sensor (second); replace the left side impact sensor (second) Side Impact Sensor (Second) Removal and Installation (4-door), then clear the DTC.

9. Left side impact sensor (first) substituting:

Left side impact sensor (first) substituting
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the negative cable from the battery, then wait at least 3 minutes.

-3. Return the left side impact sensor (second) which was replaced in step 8.

-4. Substitute a known-good left side impact sensor (first) Side Impact Sensor (First) Removal and Installation (4-door).

-5. Reconnect the negative cable to the battery.

-6. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-7. Turn the ignition switch to ON (II), then wait for 10 seconds.

-8. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 45-11 indicated?
-YES- Go to step 10.
-NO- Faulty original left side impact sensor (first); replace the left side impact sensor (first) Side Impact Sensor (First) Removal and Installation (4-door), then clear the DTC.

10. Shorted wire check (LS2+ line to LS2- line):

Shorted wire check (LS2+ line to LS2- line)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the negative cable from the battery, then wait at least 3 minutes.

-3. Disconnect the following connectors.





-4. Measure the resistance between test points 1 and 2.









Is there an open circuit, or at least 1 MOhms?
-YES- Go to step 11.
-NO- Short to another wire in the floor wire harness between the left side impact sensor (first) and the left side impact sensor (second); replace the floor wire harness, then clear the DTC.

11. Shorted wire check (LS2+, LS2- lines):

Shorted wire check (LS2+, LS2- lines)
-1. Measure the resistance between test points 1 and 2.














Is there an open circuit, or at least 1 MOhms?
-YES- Go to step 12.
-NO- Short to ground in the floor wire harness between the left side impact sensor (first) and the left side impact sensor (second); replace the floor wire harness, then clear the DTC.

12. Shorted wire check (LS2+, LS2- lines to power):

Shorted wire check (LS2+, LS2- lines to power)
-1. Reconnect the negative cable to the battery.

-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.














Is there less than 0.2 V?
-YES- Go to step 13.
-NO- Short to power in the floor wire harness between the left side impact sensor (first) and the left side impact sensor (second); replace the floor wire harness, then clear the DTC.

13. Open wire check (LS2+, LS2- lines):

Open wire check (LS2+, LS2- lines)
-1. Turn the ignition switch to LOCK (0).

-2. Measure the resistance between test points 1 and 2.














Is there less than 1.0 Ohms?
-YES- Disconnect and reconnect the connector, and then check the DTC again. If the DTC is still present, replace the SRS unit Service and Repair.
-NO- Open in the floor wire harness between the left side impact sensor (first) and the left side impact sensor (second); replace the floor wire harness, then clear the DTC.

14. Connector and harness visual check:

Connector and harness visual check
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the negative cable from the battery, then wait at least 3 minutes.

-3. Check the following connectors and harness.





Are the connectors and harness OK?
-YES- Go to step 16.
-NO- Go to step 15.

15. System check 2:

System check 2
-1. Repair the poor connector connections or replace the harness whichever was the cause of the problem in step 14.

-2. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-3. Turn the ignition switch to ON (II), then wait for 10 seconds.

-4. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 43-11 indicated?
-YES- Turn the ignition switch to LOCK (0), then go to step 16.
-NO- Troubleshooting is complete.

16. Left side impact sensor (first) substituting:

Left side impact sensor (first) substituting
-1. Substitute a known-good left side impact sensor (first).

-2. Reconnect the negative cable to the battery.

-3. Clear the DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

-4. Turn the ignition switch to ON (II), then wait for 10 seconds.

-5. Check for DTCs with the HDS Reading and Clearing Diagnostic Trouble Codes.

Is DTC 43-11 indicated?
-YES- Go to step 17.
-NO- Faulty original left side impact sensor (first); replace the left side impact sensor (first) Side Impact Sensor (First) Removal and Installation (4-door), then clear the DTC.

17. Shorted wire check (LS1+ line to LS1- line):

Shorted wire check (LS1+ line to LS1- line)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the negative cable from the battery, then wait at least 3 minutes.

-3. Disconnect the following connectors.





-4. Measure the resistance between test points 1 and 2.









Is there an open circuit, or at least 1 MOhms?
-YES- Go to step 18.
-NO- Short to another wire in the floor wire harness between the SRS unit and the left side impact sensor (first); replace the floor wire harness, then clear the DTC.

18. Shorted wire check (LS1+, LS1- lines):

Shorted wire check (LS1+, LS1- lines)
-1. Measure the resistance between test points 1 and 2.














Is there an open circuit, or at least 1 MOhms?
-YES- Go to step 19.
-NO- Short to ground in the floor wire harness between the SRS unit and the left side impact sensor (first); replace the floor wire harness, then clear the DTC.

19. Shorted wire check (LS1+, LS1- lines to power):

Shorted wire check (LS1+, LS1- lines to power)
-1. Reconnect the negative cable to the battery.

-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.














Is there less than 0.2 V?
-YES- Go to step 20.
-NO- Short to power in the floor wire harness between the SRS unit and the left side impact sensor (first); replace the floor wire harness, then clear the DTC.

20. Open wire check (LS1+, LS1- lines):

Open wire check (LS1+, LS1- lines)
-1. Turn the ignition switch to LOCK (0).

-2. Measure the resistance between test points 1 and 2.














Is there less than 1.0 Ohms?
-YES- Disconnect and reconnect the connector, and then check the DTC again. If the DTC is still present, replace the SRS unit Service and Repair.
-NO- Open in the floor wire harness between the SRS unit and the left side impact sensor (first); replace the floor wire harness, then clear the DTC.