DTC 26

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) performs TURN-ON tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM monitors the six firing loops to detect leakage currents to ground and system voltage in the frontal and side air bag inflator module and seat belt pretensioner circuits. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure they are within their respective normal resistance ranges. Upon passing these tests, and if the energy reserve is charged up, the firing transistors are tested. The SDM then goes into CONTINUOUS MONITORING mode. The SDM service wait time is 1 minute. Refer to Air Bag(s) Arming and Disarming.

Conditions for Setting the DTC
^ The ignition is within normal operating voltage range.
^ The measured leakage currents to system voltage in the passenger seat belt pretensioner deployment loop are above a specified value caused by a short circuit between the passenger seat belt pretensioner deployment loop and system voltage.

DTC 26 will set once one of these conditions is met. This test is run during the SDM Turn-ON tests.

Action Taken When the DTC Sets
^ The SDM sets a Diagnostic Trouble Code.
^ The SDM turns ON the AIR BAG warning lamp.

Conditions for Clearing the DTC
Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the Current DTC 26 to set are no longer existing, History DTC 26 will set. History DTC 26 may be cleared using the scan tool.

Diagnostic Aids
A short circuit to a voltage source in the passenger seat belt pretensioner circuit or a short circuit between the communication signal line of the LH or RH inflatable restraint Side Impact Sensor (SIS) can set this DTC. Inspect CKTs AB900, AB950, XB901 or XB950 carefully for cutting and/or chafing.

^ If DTC 26 and DTC 73 are set, inspect CKTs AB900, AB950, XB901, XB950 and B41 carefully for cutting and/or chafing.
^ If DTC 26 and DTC 83 are set, inspect AM900, AM950, XM901, XM950 and M44 carefully for cutting and/or chafing.

When measurements are requested in this table, use J 39200.

Test Description
The numbers below refer to step numbers on the diagnostic table.

2. This test checks for a damaged or corroded SDM harness connector.
7. This test determines whether the malfunction is in CKT AB900 or CKT AB950 in the SIR wiring harness.
9. This test determines whether the malfunction is in CKT XB901 or CKT XB950 in the SIR wiring harness.
11. This test determines whether the malfunction is in CKT AB900 in the passenger seat wiring harness.
12. This test determines whether the malfunction is in CKT XB901 in the passenger seat wiring harness.