For 1990-2009 cars

Table 1: | DTC B1071 Internal SDM Failure

### Circuit Description

DTC B1071 is an indication of a potential internal inflatable restraint sensing and diagnostic module (SDM) malfunction. DTC B1071 will set upon detection of any condition in the table below.

### Conditions for Setting the DTC

Malfunction | Detection Test
--- | ---
23 VLR voltage out of normal operating range. | Power-On, Continuous Monitoring
Crash data recording reserve voltage discharge time failure for three consecutive ignition cycles. | Power-On
The calculated checksum for internal memory does not match the stored value. | Power-On
The driver or passenger deployment loop is shorted to ground. | Continuous Monitoring
The Accelerometer is malfunctioning. | Power-On, Continuous Monitoring
The driver or passenger current source is malfunctioning. | Resistance Measurement
The temporary memory storage area is malfunctioning. | Power-On
The inflatable restraint sensing and diagnostic module (SDM) is unable to read from or write to EEPROM. | Power-On
The arming sensor inside the inflatable restraint sensing and diagnostic module (SDM) is not closed during a deployment event. | Asynchronously
The voltage measured at Driver Low and Passenger Low is too low. | Power-On, Continuous Monitoring
The device inside the inflatable restraint sensing and diagnostic module (SDM) that arms the system for deployment is malfunctioning. | Power-On, Continuous Monitoring
The permanent memory storage area is malfunctioning. | Power-On

### 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 MIL/DTC

• | Current DTC -- The malfunction has not been detected for 500 milliseconds.

• | History DTC

- | You issue a scan tool Clear DTCs command.

- | 250 ignition cycles have passed since the last malfunction.

### Diagnostic Aids

When you issue a scan tool Clear DTCs command, some of the indicated malfunctions will only allow the AIR BAG warning lamp to turn off briefly then turn back ON.

#### DTC B1071 Internal SDM Failure

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Notice: When DTC B1018 or B1024 has been set it is necessary to replace the inflatable restraint Sensing and Diagnostic Module (SDM). Setting DTC B1018 or B1024 will also cause DTC B1071 to set. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1018 or B1024 and DTC B1071 will remain current. Make sure that the short to ground condition is repaired prior to installing a replacement SDM to avoid damaging the SDM.
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 | Is DTC B1018 set? | -- | Go to DTC B1018 Passenger Deployment Loop Short to GND | Go to Step 3
3 | Is DTC B1024 set? | -- | Go to DTC B1024 Driver Deployment Loop Short to Ground | Go to Step 4
4 |

1. Turn the ignition switch OFF.
2. Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Has the SDM been replaced?

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Go to SIR Diagnostic System Check

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