U0170

U0170-LOST COMMUNICATION W/UP-FRONT LEFT SATELLITE ACCELERATION SENSOR

Special Tools:

For a complete wiring diagram, refer to the Wiring Information.

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. Refer to the enclosed graphic as a reference of specific Side Impact Satellite Acceleration, Side Impact Satellite Pressure, and Up-Front Satellite Acceleration sensor locations on the vehicle. It is important to review this graphic thoroughly to understand the specific area of diagnosis you are looking to complete.

The Up-Front Right and Up-Front Left Satellite Acceleration Sensors are located behind the Front End Module carrier in the engine area. The number 1 side sensors are located in the 1st row door area with the number 1 side sensor being on the passenger side (Right Side Satellite Pressure Sensor 1) and the number 1 side sensor also being on the driver side (Left Side Satellite Pressure Sensor 1). The number 4 side sensors are located in the "B" pillar area just past the 1st row doors. The number 4 side sensor is located on the passenger side (Right Side Satellite Acceleration Sensor 4) and the number 4 side sensor is also located on the driver side (Left Side Satellite Acceleration Sensor 4). The number 2 side sensors are located in the "C" pillar area just past the 2nd row doors. The number 2 side sensor is located on the passenger side (Right Side Satellite Acceleration Sensor 2) and the number 2 side sensor is also located on the driver side (Left Side Satellite Acceleration Sensor 2). The number 3 side sensors are located in the 3rd row area just above the rear axle. The number 3 side sensor is located on the passenger side (Right Side Satellite Acceleration Sensor 3) and the number 3 side sensor is also located on the driver side (Left Side Satellite Acceleration Sensor 3).

- When Monitored:
The ORC monitors communication with the impact sensor continuously.

- Set Condition:
This DTC sets when the ORC no longer receives notification of the status update from 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. DETERMINE ACTIVE OR STORED DTC

NOTE: Make sure the battery is fully charged.

1. Turn the ignition on.
2. With the scan tool, read ORC DTCs.

Is the DTC active or stored?

ORC - ACTIVE DTC

- Go To 2

ORC - STORED DTC

- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST. . Restraints System Intermittent Condition Test

2. CHECK FOR ADDITIONAL ACTIVE SATELLITE SENSOR DTCS

NOTE: The scan tool, (8443-28) , and a DVOM are required to perform the following tests.

1. With the scan tool, read all active ORC DTCs.

Is DTC U0171-LOST COMMUNICATION W/UP-FRONT RIGHT SATELLITE ACCELERATION SENSOR also active?

Yes

- Go To 8

No

- Go To 3

3. CHECK (R79) LEFT FRONT IMPACT SENSOR SIGNAL CIRCUIT FOR AN OPEN

1. Measure the resistance of the (R81) Left Front Impact Sensor Ground circuit between the Left Front Impact Sensor harness connector and the (8443-28).

Is the resistance below 1.0 Ohm?

Yes

- Go To 5

No

- Repair or replace the (R81) Left Front Impact Sensor Ground circuit for an open.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

5. CHECK (R79) LEFT FRONT IMPACT SENSOR SIGNAL CIRCUIT FOR A SHORT TO THE (R81) LEFT FRONT IMPACT SENSOR GROUND CIRCUIT

1. Measure the resistance between the (R79) Left Front Impact Sensor Signal circuit and the (R81) Left Front Impact Sensor Ground circuit at the Left Front Impact Sensor harness connector.

Is the resistance below 5K Ohms?

Yes

- Repair or replace the (R79) Left Front Impact Sensor Signal circuit for a short to the (R81) Left Front Impact Sensor Ground circuit.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Go To 6

6. CHECK (R79) LEFT FRONT IMPACT SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

1. Measure the resistance of the (R79) Left Front Impact Sensor Signal circuit between ground and the Left Front Impact Sensor harness connector.

Is the resistance below 6K Ohms?

Yes

- Repair or replace the (R79) Left Front Impact Sensor Signal circuit for a short to ground.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Go To 7

7. CHECK (R79) LEFT FRONT IMPACT SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

If equipped with the standard key ignition, use this ignition on warning.

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.
If equipped with the keyless ignition, use this ignition on warning.

WARNING: Disconnect the 12-volt battery wait two minutes before proceeding, remove the ORC fuses, connect the 12-volt battery, wait two minutes before proceeding. Cycle the ignition to the On position, then reconnect the ORC fuses. Wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

1. Measure the voltage of the (R79) Left Front Impact Sensor Signal circuit between the Left Front Impact Sensor harness connector and ground.

Is there any voltage present?

Yes

- 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.
- Repair or replace the (R79) Left Front Impact Sensor Signal circuit for a short to voltage.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test. If DTC U0170-LOST COMMUNICATION W/UP-LEFT FRONT SATELLITE ACCELERATION SENSOR is still active, Go To 9. Otherwise, test complete.

8. CHECK (R81) LEFT FRONT IMPACT SENSOR GROUND CIRCUIT AND (R82) RIGHT FRONT IMPACT SENSOR GROUND CIRCUIT FOR A SHORT TO VOLTAGE

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. Disconnect the Left Front Impact Sensor harness connector.
2. Disconnect the Right Front Impact Sensor harness connector.
3. Disconnect the ORC harness connectors.

NOTE: Check the connectors - Clean and repair as necessary.

4. Connect the (8443-28) to the ORC harness connectors. If equipped with the standard key ignition, use this ignition on warning.

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.
If equipped with the keyless ignition, use this ignition on warning.

WARNING: Disconnect the 12-volt battery wait two minutes before proceeding, remove the ORC fuses, connect the 12-volt battery, wait two minutes before proceeding. Cycle the ignition to the On position, then reconnect the ORC fuses. Wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

5. Measure the voltage of the (R81) Left Front Impact Sensor Ground circuit between the (8443-28) and ground.
6. Measure the voltage of the (R82) Right Front Impact Sensor Ground circuit between the (8443-28) and ground.

Is there any voltage present on either circuit?

Yes

- 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.
- Repair or replace the impact sensor circuit with voltage present for a short to voltage.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Go To 9

9. CHECK OPERATION OF LEFT FRONT IMPACT SENSOR

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. Replace the Left Front Impact Sensor. . Impact Sensor - Removal
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. If equipped with the standard key ignition, use this ignition on warning.

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.
If equipped with the keyless ignition, use this ignition on warning.

WARNING: Disconnect the 12-volt battery wait two minutes before proceeding, remove the ORC fuses, connect the 12-volt battery, wait two minutes before proceeding. Cycle the ignition to the On position, then reconnect the ORC fuses. 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. With the scan tool, erase all codes in the ORC.
6. Perform ORC module reset. Access the Miscellaneous Function or Diagnostic Procedures menu from the ORC ECU Overview screen on the scan tool to perform this operation.
7. Wait one minute, and read active codes.

Did the active DTC U0170-LOST COMMUNICATION W/UP-LEFT FRONT SATELLITE ACCELERATION SENSOR return?

Yes

- WARNING: If the Occupant Restraint Controller (ORC) is dropped at any time, it must be replaced. Failure to take the proper precautions can result in accidental airbag deployment. Failure to follow these instructions may result in possible serious or fatal injury.
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.

- Replace the ORC. Occupant Restraint Controller - Removal.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Repair is complete.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.