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For 1990-2009 cars only

Object Number: 420272  Size: MF
SIR Handling Caution
SIR Handling Caution
SIR Handling Caution
SIR Handling Caution
SIR Handling Caution
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice

Circuit Description

When you first turn the ignition switch to the ON position, The inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Next the SDM measures IGNITION 1 and the deployment loop voltages to make sure they are within their respective normal voltage ranges. Then the SDM proceeds with the Resistance Measurement test. During one portion of the Resistance Measurement test, the SDM does the following:

    • Grounds the Passenger Side Low terminal 3 through an internal current sink.
    • Connects the Passenger Side High terminal 4 to an internal constant current source . This current produces proportional voltage drops in the deployment loop.
    • Measures the voltage difference between the Passenger Side High and Passenger Side Low.
    • Calculates the resistance of the passenger deployment loop using the measured voltage.

Conditions for Setting the DTC

    • The driver and passenger deployment loops are not open.
    • The driver and passenger deployment loops are not shorted to voltage.
    • The passenger deployment loop is not shorted to ground.
    • The passenger deployment loop resistance is less than 1.4 ohms. The passenger deployment loop consists of the following components:
       - An inflatable restraint IP module.
       - A harness wiring of the YEL /RED wire.
       - A harness wiring of the YEL wire.
       - A connector terminal contact.

The Resistance Measurement test checks for this malfunction. This test only occurs once each ignition cycle when the IGNITION 1 is within the normal operating voltage range.

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

    • Clear the Current DTC when the resistance of the passenger deployment loop is more than 1.4 ohms and the ignition switch is cycled.
    • Clear the History DTC under the following conditions:
       - You issue a scan tool CLEAR CODES command.
       - 250 malfunction free ignition cycles have occurred.

When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

Diagnostic Aids

The following can cause an intermittent condition:

    • A short circuit between the YEL/RED wire and the GRN /RED wire.
    • A short circuit between the YEL/RED wire and the GRN wire.
    • A short circuit between the YEL/RED wire and the YEL wire.
    • A malfunctioning shorting bar on the inflatable restraint IP module connector.
        When a scan tool CLEAR CODES command is still present, the DTC will not reappear until the next ignition cycle.

Test Description

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

  1. This test determines the deployment loop resistance that the Sensing and Diagnostic Module (SDM) measures.

  2. This test isolates the malfunction to one side of the yellow connector of the inflatable restraint IP module. This is done by substituting the known good resistance of the load tool, then observing if the malfunction is still present.

  3. This test checks for a short from the YEL/RED wire to the YEL wire.

  4. This test checks for a short from the YEL/RED wire to the GRN wire.

DTC B1016 Passenger Deployment Loop Resistance Low

Step

Action

Values

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn the ignition switch to the LOCK position.
  2. Connect a scan tool to the data link connector. Follow the directions in the scan tool instruction manual.
  3. Turn the ignition switch to the ON position.
  4. Request the SIR data list display.
  5. Read the passenger deployment loop resistance, and record PASSENGER RESISTANCE on the repair order.
  6. Request the display of the SIR diagnostic trouble codes.

Is DTC B1022 also current?

--

Go to Step 3

Go to Step 4

3

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the yellow connectors of the inflatable restraint steering wheel module and of the inflatable restraint IP modules.The connectors are under the steering wheel side cap and behind the IP compartment.
  3. Repair the short from the GRN/RED wire to the YEL/RED wire.

Is the circuit repair complete?

--

Go to Step 12

--

4

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the yellow connector of the inflatable restraint IP module behind the IP compartment.
  3. Reconnect the yellow connector of the inflatable restraint IP module behind the IP compartment.
  4. Ensure the connector is correctly seated and the CPA is installed correctly.
  5. Turn the ignition switch to the ON position.
  6. Using the scan tool, display the SIR data list.Read the PASSENGER RESISTANCE.

Is PASSENGER RESISTANCE less than the specified value?

1.4 ohms

Go to Step 6

Go to Step 5

5

  1. Turn the ignition switch to the LOCK position.
  2. Replace the harness connector of the inflatable restraint IP module. Refer to SIR Connector (Plastic Body and Terminal Metal Pin) Repair portion of Wiring Repair in this section.

Did you replace the harness connector of the inflatable restraint IP module?

--

Go to Step 12

--

6

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the yellow connector of the inflatable restraint IP module behind the IP compartment.
  3. Connect the J 38715-A SIR Driver/Passenger Load Tool to the harness connectors of the inflatable restraint steering wheel module and of the inflatable restraint IP module.
  4. Turn the ignition switch to the ON position.
  5. Using the scan tool, display the SIR data list. Read the PASSENGER RESISTANCE.

Is PASSENGER RESISTANCE less than the specified value?

1.4 ohms

Go to Step 8

Go to Step 7

7

  1. Turn the ignition switch to the LOCK position.
  2. Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement in this section.

Did you replace the inflatable restraint IP module?

--

Go to Step 12

--

8

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the Sensing and Diagnostic Module (SDM).
  3. Disconnect the J 38715-A .
  4. Measure the resistance from the SDM harness connector terminal 3 to terminal 4.

Is the resistance reading less than the specified value?

OL

(Infinite)

Go to Step 9

Go to Step 10

9

  1. Turn the ignition switch to the LOCK position.
  2. Repair the short from the YEL wire to the YEL/RED wire.

Is the short repair complete?

--

Go to Step 12

--

10

Measure the resistance from the SDM harness connector terminal 4 to terminal 10.

Is the resistance reading less than the specified value?

OL

(Infinite)

Go to Step 11

Go to Sensing and Diagnostic Module Integrity Check

11

Repair the short from the YEL/RED wire to the GRN wire.

Is the short repair complete?

--

Go to Step 12

--

12

  1. Reconnect all SIR system components.
  2. Confirm that all the components are correctly mounted.

Are all the SIR components connected and correctly mounted?

--

Go to Step 13

--

13

Clear the SIR diagnostic trouble codes.

Did you clear the SIR diagnostic trouble codes?

--

Go to SIR Diagnostic System Check

--