B0018

DTC B0018 RF/Passenger Frontal Deployment Loop (Single Stage or Stage 1) Short to Ground/Voltage Out of Range

Schematic:

CIRCUIT DESCRIPTION
The passenger frontal air bag deployment loop is a 2 wire circuit. One wire is the high side of the loop while the other is the low side of the loop. When you first turn the ignition switch ON, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions 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 RUNNING THE DTC
The SDM monitors the passenger frontal air bag deployment loop with power on.

CONDITIONS FOR SETTING THE DTC
^ If the SDM detects the voltage at the passenger frontal high and is greater than 6 Volts for 5 consecutive samples, the SDM sets this DTC.
^ Passenger frontal high is less than 2.4 Volts and passenger frontal high to low side resistance is less than 6 Ohm for 5 consecutive samples, the SDM sets this DTC.

The passenger frontal deployment loop consists of the following components:
^ Inflatable restraint IP module.
^ Harness wiring of passenger frontal high and low deployment circuits.
^ Connector terminal contact.

ACTION TAKEN WHEN THE DTC SETS
^ The SDM sets a DTC.
^ The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

CONDITIONS FOR CLEARING THE DTC
The DTC is cleared from the current file and stored as a history DTC
^ Current DTC
- Passenger frontal high is less than or equal to 6 Volts for 5 consecutive samples.
- Passenger frontal high is greater than or equal to 2.4 Volts and passenger frontal high to low resistance is less than 6 Ohm for 5 consecutive samples.
- CLEAR CODES command
^ History DTC
- You issue a scan tool CLEAR CODES command.
- Once 255 malfunction free ignition cycles have occurred.
^ When the SDM detect that no DTCs are present, the SDM commands the AIR BAG warning lamp to be turn OFF.

DIAGNOSTIC AIDS
If the DTC is stored as a history DTC the deployment circuit must be checked for:
^ Frayed insulation
^ Damaged connectors
^ Moisture damage
^ Stretched/broken wires
The fact that the DTC set and now is stored as a history DTC indicates a short to ground or to voltage on either of the two sides of the deployment circuit has happened in the past. The short to ground or voltage will prevent deployment if it happens again during a commanded air bag deployment.

TEST DESCRIPTION

Test Step 1 - Step 6:

Test Step 7 - Step 16:

The number(s) below refer to the step number(s) on the diagnostic table.
2. This step checks the IP/passenger inflator module in-line connector.
5. This step checks to see if there is a malfunctioning inflatable restraint IP/passenger inflator module.
7. This step checks to see if there is a short to ground in the passenger frontal high deployment circuit.
9. This step checks to see if there is a short to ground in the passenger frontal low deployment circuit.
11. This step checks to see if there is a short to voltage in the passenger frontal high deployment circuit.
13. This step determines if there is a short to voltage in the passenger frontal low deployment circuit or if there is a malfunctioning SDM.
16. This step clears all SIR DTC's.