U0172
U0172-00-LOST COMMUNICATION W/ LEFT SIDE SATELLITE SENSOR 1
Special Tools
For a complete wiring diagram Refer to Diagrams/Electrical.
Theory of Operation
The location of this left side impact sensor 1 is in the B-pillar just past the first row seating. 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. If the scan tool shows this DTC has a Stored history of setting then the left side impact sensor is to be replaced. A short to voltage fault on the left side impact sensor 1 sensor wiring can cause a loss of comm impact sensor 2 code to set and the possible replacement of a good left side impact sensor 2. The left side impact 1, and 2 sensors are wired in a daisy chain pattern. The short to battery fault in a loss of comm or internal circuit failure of the side impact sensor 1 can cause the impact sensor 2 on the same side to set a loss of comm code.
- When Monitored:
The Occupant Restraint Controller (ORC) continuously communicates with the Left Side Impact Sensor 1 over the sensor signal circuit. The sensor communication and on board diagnostics are powered by the ORC signal.
- Set Condition:
This Diagnostic Trouble Code (DTC) will set, if the ORC and the Left Side Impact Sensor 1 fail to establish and maintain valid data communications.
Possible Causes:
Always Perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Restraints System Pre-Diagnostic Procedure
1. VERIFY ACTIVE DTC
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.
NOTE: Using the wiring diagram/schematic as a guide check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
NOTE: If after the harness inspection it appears the impact sensor connector is only seated halfway. Reseat the harness connector into the impact sensor and lock the tab. Follow the instructions below checking for active codes.
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.
NOTE: Make sure the battery is fully charged.
1. Turn the ignition on.
2. With the scan tool, read ORC DTCs.
Does the scan tool display active B0091-49-LEFT SIDE ACCELERATION SENSOR 1 - INTERNAL ELECTRONIC FAILURE. U0172-00-LOST COMMUNICATION W/ LEFT SIDE SATELLITE SENSOR 1. U0173-00-LOST COMMUNICATION W/ LEFT SIDE SATELLITE SENSOR 2. U11AD-00-LOST COMMUNICATION W/ LEFT SIDE SATELLITE SENSOR 4 - DTC?
Yes
- Check for all other internal and lost communication codes indicated in the left side impact sensor daisy chain wiring after diagnosing DTC B0091-49-LEFT SIDE ACCELERATION SENSOR 1 - INTERNAL ELECTRONIC FAILURE, and DTC U0172-LOST COMMUNICATION W/ LEFT SIDE SATELLITE ACCELERATION SENSOR 1. Go To The DTC Displayed Go To 2
No
- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST. Restraints System Intermittent Condition Test
2. CHECK THE (R13, R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS 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 Side Impact Sensor 1 harness connector.
2. Disconnect the ORC harness connectors.
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 (R13) Left Side Impact Sensor 1 Signal circuit at the Left Side Impact Sensor 1 harness connector cavity 4.
4. Measure the voltage of the (R15) Left Side Impact Sensor 1 Ground circuit at the Left Side Impact Sensor 1 harness connector cavity 3.
Is there any voltage present?
Yes
- Repair the (R13, R15) Left Side Impact Sensor 1 circuits for a short to voltage.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
No
- Go To 3
3. CHECK THE (R13, R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS 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 between ground and the (R13) Left Side Impact Sensor 1 Signal circuit at the Left Side Impact Sensor 1 harness connector cavity 4.
2. Measure the resistance between ground and the (R15) Left Side Impact Sensor 1 Ground circuit at the Left Side Impact Sensor 1 harness connector cavity 3.
Is the resistance below 100K Ohms?
Yes
- Repair the (R13, R15) Left Side Impact Sensor 1 circuit for a short to ground.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
No
- Go To 4
4. CHECK THE (R13, R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS FOR A SHORT TOGETHER
1. Measure the resistance between the (R13) Left Side Impact Sensor 1 Signal circuit and (R15) Left Side Impact Sensor 1 Ground circuit at the Left Side Impact Sensor 1 harness connector cavity 3 and 4.
Is the resistance below 100K Ohms?
Yes
- Repair the (R13, R15) Left Side Impact Sensor 1 circuits shorted together.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
No
- Go To 5
5. CHECK THE (R15) LEFT SIDE IMPACT SENSOR 1 GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Connect the SRS Load Tool Adapter 8443-24 to the ORC C1 harness connector.
2. Measure the resistance of the (R15) Left Side Impact Sensor 1 Ground circuit between the Left Side Impact Sensor 1 harness connector and the SRS Load Tool Adapter 8443-24 cavity 19.
Is the resistance below 1 Ohm?
Yes
- Go To 6
No
- Repair the (R15) Left Side Impact Sensor 1 Ground circuit for an open or high resistance.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
6. CHECK THE (R13) LEFT SIDE IMPACT SENSOR 1 CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (R13) Left Side Impact Sensor 1 Signal circuit between the Left Side Impact Sensor 1 harness connector and the SRS Load Tool Adapter cavity 11.
Is the resistance below 1 Ohm?
Yes
- Go To 7
No
- Repair the (R13) Left Side Impact Sensor 1 Signal circuit for an open or high resistance.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
7. CHECK OPERATION OF THE LEFT SIDE IMPACT SENSOR 1
1. Replace the Left Side Impact Sensor 1 in accordance with the Service Information.
2. Reconnect the vehicle body harness connector 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.
Does the scan tool display active U0172-00-LOST COMMUNICATION W/ LEFT SIDE SATELLITE SENSOR 1- DTC?
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.
- WARNING:If the Occupant Restraint Controller (ORC) is dropped at any time, it must be replaced. Failure to follow these instructions may result in possible serious or fatal injury.
- Replace the ORC in accordance with Service Instructions.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test
No
- Repair is complete.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test