DTC 71

Circuit Description
DTC 71 is an indication of a potential internal SDM malfunction and will set if any of the following conditions is detected:
- Reserve voltage discharge time has failed for three consecutive ignition cycles.
- The calculated checksum for internal memory does not match the stored value.
- The temporary memory storage area is malfunctioning.
- The permanent memory storage area is malfunctioning.
- The voltage measured at driver low and passenger low are too high.
- The voltage measured at driver low and passenger low are too low.
- The. accelerometer inside the SDM is malfunctioning.
- The driver current source and/or passenger current source is malfunctioning.
- The SDM is unable to read from or write to electronically erasable programmable read only memory (EEPROM).
- The arming sensor inside the SDM is not closed during a deployment event.

DTC 71 Will Set When
Any of the indicated malfunctions is detected by the SDM. The malfunctions are detected at various times:
- Turn-on.
- Continuous monitoring.
- Resistance measurement test.

Action Taken
The SDM turns on the AIRBAG indicator and sets a DTC 71.
DTC 71 Will Clear When A scan tool CLEAR CODES command is received by the SDM. Some of the malfunctions will allow the AIRBAG indicator to turn off only briefly and then turn on again.

Test Description
The number(s) below refer to step(s) on the diagnostic table.

3. See the cautions below.

Steps 1 - 3:

DTC 71 - Internal Sensing and Diagnostic Module (SDM) Failure

CAUTION: The SDM can maintain sufficient voltage to deploy the airbags for 10 minutes after the ignition is OFF and the fuse has been removed. It the air - bags are not disconnected, service cannot begin until 10 minutes have passed after disconnecting power to the SDM.

CAUTION: During service procedures, be very careful when handling the SDM. Never strike or jar the SDM. Never power up the SIR system when the SDM is not rigidly attached to the vehicle. All SDM mounting bolts must be carefully tightened, and the SDM arrow must be pointing toward the front of the vehicle to ensure proper operation of the SIR system. The SDM could be activated if it is powered when it is not rigidly attached to the vehicle, resulting in unexpected deployment and possible injury.

Important: Codes 18, 24, and 71 cannot be reset it there has been a short to ground in the deployment loops. When DTC 18 or 24 has been set, it is necessary to replace the SDM. To avoid damaging the replacement SDM, ensure that the short to ground is repaired prior to installing a replacement SDM.