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 is set by the 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 SIDE LOW and PASSENGER SIDE LOW is too low. | Power-On, Continuous monitoring
The device inside the Inflatable Restraint Sensing and Diagnostic Module 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 attempts to turn on the AIR BAG warning lamp.

### Conditions for Clearing the DTC

• | Current DTC

| The malfunction has not been detected for 500 milliseconds.

• | History DTC

- | You issue a scan tool CLEAR CODES command.

- | 250 ignition cycles have occurred without a malfunction.

### Diagnostic Aids

DTC B1071 indicates a fault within the SDM. Replace the SDM if DTC B1071 indicates a fault within the SDM. Replace the SDM if DTC B1071 sets, current or history.

Notice: When DTC B1019 or B1025 is set, it is necessary to replace the inflatable restraint Sensing and Diagnostic Module (SDM). Setting DTC B1019 or B1025 also causes DTC B1071 to set. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1019 or B1025 and DTC B1071 will remain current. Ensure that the short to ground condition is repaired prior to installing a replacement SDM in order to avoid damaging the SDM.

#### DTC B1071 Internal SDM Failure

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 | Is DTC B1019 also set? | -- | Go to DTC B1019 Passenger Deploy. Loop Short to Voltage | Go to Step 3
3 | Is DTC B1025 also set? | -- | Go to DTC B1025 Driver Deployment Loop Short to Voltage | Go to Step 4
4 |

1. Turn the ignition switch to the LOCK position.
2. Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you replace the SDM?

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Go to SIR Diagnostic System Check

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