B1018

Circuit Description
When you first turn the ignition switch to the RUN position, the supplemental restraint sensing and diagnostic module (SDM) performs tests in order to diagnose critical malfunctions within the SDM. Upon passing these tests, the following circuits are measured in order to ensure that they are within their respective normal voltage ranges:
- IGNITION 1
- 23 VLR
- Deployment loop voltages

The SDM monitors the voltage at the DRIVER SIDE LOW terminal 3 and the PASSENGER SIDE LOW terminal 4 in order to detect shorts to ground in the inflator module circuits. The service wait time is 10 minutes. Refer to SRS Service Precautions.

Conditions for Setting the DTC
- The driver and the passenger deployment loops are not open.
- The driver deployment loop is not shorted to voltage.
- The voltage at the DRIVER SIDE LOW terminal 3 is more than 3.3 volts.
- The voltage at PASSENGER SIDE LOW terminal 4 is less than 3.3 volts for 500 milliseconds.

The following tests inspect for the DTC. These tests occur when IGNITION 1 is within the normal operating voltage range.

- POWER-ON
When the malfunction is detected in this test, the RESISTANCE MEASUREMENT test will not be performed.

- CONTINUOUS MONITORING

Action Taken When the DTC Sets
- The SDM sets DTC B1018.
- The SDM sets DTC B1071.
- The SDM turns the AIR BAG warning lamp to the ON position.

Conditions for Clearing the DTC
DTC B1018 is a latched code. You cannot clear a latched code. Repair the malfunction that set this DTC before you replace the SDM.

Diagnostic Aids
A short to ground in the supplemental restraint IP module circuit may cause an intermittent condition. A DTC B1018 would be accompanied by DTC B1071. Inspect CKT 1403 and CKT 1404 carefully for cutting or chafing. Wiring pigtail damage requires replacement of the supplemental restraint IP module. A careful inspection of the circuits and components indicated on the DTC B1018 table is essential in order to prevent damage to the replacement supplemental restraint sensing and diagnostic module (SDM). The diagnostic table directs the technician to note the entry value of PASSENGER SENSELO. Comparing the value of PASSENGER SENSELO maybe helpful in determining if an intermittent condition exists.
When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616-A Connector Test Adapter kit. When an inspection for proper connection is requested, refer to Intermittents and Poor Connections. When a wire, connector or terminal repair is requested, use J 38125-B Terminal Repair Kit and refer to Wiring Repair.

Step 1 - 2:

Steps 3 - 4:

Steps 5 - 8:

Step 9:

Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. This test determines the passenger side low voltage which is measured by the supplemental restraint sensing and diagnostic module (SDM).
3. This test isolates the malfunction to one side of the supplemental restraint IP module yellow 2-way connector.
5. This test determines whether the malfunction is in CKT 1403.
7. This test determines whether the malfunction is in CKT 1404.