B0018

Circuit Description

When you first turn the ignition switch to the RUN position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical multifunctions within itself. Then the SDM performs the following continuous diagnostic tests on the deployment loops

^ Deployment loop voltage out of range test

^ Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

Conditions for Setting the DTC

^ Deployment loop voltage out of range test.

- Ignition 1 voltage is within the normal operating voltage range.

- Passenger frontal high terminal A3 is more than 6 volts for 300 milliseconds.

^ Deployment loop resistance measurement test.

- Ignition 1 voltage is within the normal operating voltage range.

- Passenger frontal deployment loop is not shorted to voltage.

- Passenger frontal high terminal A3 is less than 2 volts AND passenger frontal deployment loop resistance is less than 6 ohms for 300 milliseconds.

The passenger frontal deployment loop consists of the following components:

^ Inflatable Restraint Instrument Panel (IP) module.

^ Harness wiring of circuit 1403.

^ Harness wiring of circuit 1404.

^ Connector terminal contact.

Action Taken When the DTC Sets

^ The SDM sets a DTC B0018.

^ The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

Conditions for Clearing the DTC

^ Current DTC

- Deployment loop voltage out of range test-Passenger frontal high terminal A3 is no more than 6 volts.

- Deployment loop resistance measurement test-Passenger frontal high terminal A3 is more than 2 volts AND Passenger frontal deployment loop resistance is less than 6 ohms for 300 milliseconds.

^ History DTC

- You issue a scan tool CLEAR CODES command.

- Once 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

A short to B+ or short to ground in the Inflatable Restraint IP module circuit can cause an intermittent condition. Inspect circuit 1403 and circuit 1404 carefully for cutting or chafing. Wiring pigtail damage requires replacement of the Inflatable Restraint IP module.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

2. This step checks the inline connector C216.

5. This step checks to see if there is a malfunctioning Inflatable Restraint IP module.

7. This step checks to see if there is a short to ground in circuit 1403.

9. This step checks to see if there is a short to ground in circuit 1404.

11. This step checks to see it there is a short to B+ in circuit 1403.

13. This step determines it there is a short to B+ in circuit 1404 or if there is a malfunctioning SDM.

16. This step clears all SIR DTCs.