GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Century (China) 🢒 Restraints 🢒 SIR 🢒 DTC B0018 RF/Passenger Frontal Deployment Loop (Single Stage or Stage 1) Short to Ground/Voltage Out of Range

Object Number: 587616 Size: SF
SIR Components
SIR Schematic (2000 Buick 1 of 2)
SIR Handling Caution
Handling ESD Sensitive Parts Notice

Circuit Description

When you first turn ON the ignition, 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

Deployment loop voltage out of range test - Ignition 1 voltage is within the normal operating voltage range.

Deployment loop resistance measurement test:

    • Ignition 1 voltage is within the normal operating voltage range.
    • Passenger frontal deployment loop is not shorted to voltage.

Conditions for Setting the DTC

Deployment loop voltage out of range test - Passenger frontal high terminal A3 is more than 6 volts for 300 milliseconds.

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

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC
    • You can issue a CLEAR CODES command
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred

Diagnostic Aids

A short to B+ or a short to ground condition in the inflatable restraint IP module deployment loop can cause an intermittent condition. Inspect the passenger frontal high and passenger frontal low circuits 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.

  1. This step checks the inline connector C216.

    2.

  2. This step isolates the malfunction to one side of C216.

    3.

  3. This step checks to see if there is a short to ground in the passenger frontal high circuit.

    4.

  4. This step checks to see if there is a short to ground in the passenger frontal low circuit.

    5.

  5. This step checks to see if there is a short to B+ in the passenger frontal high circuit.

    6.

  6. This step determines if there is a short to B+ in the passenger frontal low circuit or if there is a malfunctioning SDM.

    7.

  7. This step clears all SIR and all communication DTCs.

DTC B0018 Passenger Frontal Deployment Loop Voltage Out Of Range

Step

Action

Value(s)

Yes

No

1

Did you perform the SIR Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Disconnect the inline connector C216.
  3. Inspect the male and female sides of inline connector C216 for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension
  4. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Does either the male or female side of inline connector C216 exhibit signs of corrosion, terminal damage, or poor connections?

--

Go to Step 3

Go to Step 4

3
  1. If the female side of the inline connector is damaged, the wiring harness must be replaced.
  2. If the male side of the inline connector is damaged, replace the male side of the connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

4
  1. Reconnect the inline connector C216.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the inline connectors C215 and C216.
  3. Install the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of the inline connectors C215 and C216. Use the J 38715-5 adaptor for inline connector C215 and the J 38715-90 adaptor for inline connector C215.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 7

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

7

  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Use the J 39200 Digital Multimeter (DMM) to measure the resistance between the passenger frontal high circuit and a known good ground.

Does the resistance measure less than the specified value?

OL

Go to Step 8

Go to Step 9

8

Locate and repair the short to ground in the passenger frontal high circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

9

Use the DMM the measure the resistance between the passenger frontal low circuit and a known good ground.

Does the resistance measure less than the specified value?

OL

Go to Step 10

Go to Step 11

10

Locate and repair the short to ground in the passenger frontal low circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

11

  1. Turn ON the ignition, with the engine OFF.
  2. Use the DMM to measure the voltage between the passenger frontal high circuit and a known good ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 13

Go to Step 12

12

Locate and repair the short to B+ in the passenger frontal high circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

13

Use the DMM to measure the voltage between the passenger frontal low circuit and a known good ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 15

Go to Step 14

14

Locate and repair the short to B+ in the passenger frontal low circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

15
  1. Turn OFF the ignition.
  2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16

  1. Reconnect all SIR components.
  2. Verify that all components and connectors are properly mounted.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to Diagnostic System Check - SIR

--