U0170
U0170-LOST COMMUNICATION W/UP-FRONT LEFT SATELLITE ACCELERATION SENSOR
Theory of Operation
The impact sensors perform their own self test using power supplied by the Occupant Restraint Controller (ORC) then communicate this status back to the ORC with periodic updates. The repair of this fault condition involves verifying the integrity of the wiring between the ORC and the sensor.
- When Monitored:
The impact sensor performs a self test for internal circuitry at power up during the initialization process, and continuously through the ignition cycle every 10 ms.
- Set Condition:
This DTC sets when the ORC receives notification of a self test failure within the impact sensor. Once set, this DTC is latched for the entire ignition cycle.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Restraints System Pre-Diagnostic Procedure.
1. VERIFY THAT DTC U0170-LOST COMMUNICATION W/UP-FRONT LEFT SATELLITE ACCELERATION SENSOR IS ACTIVE
NOTE: Ensure the battery is fully charged.
1. Turn the ignition on.
2. With the scan tool, read ORC DTCs.
Does the scan tool display active: U0170-LOST COMMUNICATION W/UP-FRONT LEFT SATELLITE ACCELERATION SENSOR?
Yes
- Go To 2
No
- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST . Restraints System Intermittent Condition Test
2. CHECK THE (R79, R81) FRONT LEFT IMPACT SENSOR SIGNAL AND GROUND CIRCUITS FOR A SHORT TO VOLTAGE
WARNING: Turn the ignition off, disconnect the battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
1. Disconnect the Front Left Impact Sensor connector.
2. Disconnect the ORC C2 connector.
WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
3. Measure the voltage of the (R79) Front Left Impact Sensor Signal circuit and (R81) Sensor Ground circuit at the Front Left Impact Sensor connector and ground.
Is there any voltage present?
Yes
- Repair the (R79, R81) Front Left Impact Sensor circuits for a short to voltage.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
No
- Go To 3
3. CHECK THE (R79) FRONT LEFT IMPACT SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
1. Measure the resistance of the (R79) Front Left Impact Sensor Signal circuit between the Front Left Impact Sensor connector and ground.
Is the resistance below 100K Ohms?
Yes
- Repair the (R79) Front Left Impact Sensor Signal circuit for a short to ground.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
No
- Go To 4
4. CHECK THE (R79, R81) FRONT LEFT IMPACT SENSOR CIRCUITS FOR A SHORT TOGETHER
1. Measure the resistance between the (R79) Front Left Impact Sensor Signal and (R81) Sensor Ground circuits at the Front Left Impact Sensor connector.
Is the resistance below 100K Ohms?
Yes
- Repair the (R79, R81) Front Left Impact Sensor circuits shorted together.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
No
- Go To 5
5. CHECK THE (R81) FRONT LEFT IMPACT SENSOR GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Connect the SRS Load Tool Kit 8443A to the Occupant Restraint Control Module C2 connector.
2. Measure the resistance of the (R81) Front Left Impact Sensor Ground circuit between the Front Left Impact Sensor connector and the SRS Load Tool Adapter 8443-24.
Is the resistance below 1 ohm?
Yes
- Go To 6
No
- Repair the (R81) Front Left Impact Sensor Ground circuit for an open or high resistance.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
6. CHECK THE (R79) FRONT LEFT IMPACT SENSOR CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (R79) Front Left Impact Sensor Ground circuit between the Front Left Impact Sensor connector and the SRS Load Tool Kit 8443A.
Is the resistance below 1 ohm?
Yes
- Go To 7
No
- Repair the (R79) Front Left Impact Sensor Signal circuit for an open or high resistance.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
7. CHECK OPERATION OF THE FRONT LEFT IMPACT SENSOR
1. Replace the Front Left Impact Sensor.
2. Reconnect the vehicle body harness to the impact sensor.
3. Remove any special tools or jumper wires and reconnect all previously disconnected components - except the Battery.
WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
4. Connect the scan tool to the Data Link Connector - use the most current software available.
5. Use the scan tool and erase the stored codes in all airbag system modules.
6. Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
7. Wait one minute, and read active codes and if there are none present read the stored codes.
Did the active Front Left Impact Sensor DTC return?
Yes
- Go To 8
No
- Repair is complete.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.
8. REPLACE THE OCCUPANT RESTRAINT CONTROLLER (ORC)
WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
WARNING: If the Occupant Restraint Controller (ORC) is dropped at any time, it must be replaced. Failure to take the proper precautions could result in accidental airbag deployment. Failure to follow these instructions may result in possible serious or fatal injury.
Repair
- Replace the Occupant Restraint Controller (ORC).
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST Restraints System Verification Test.