U0172-LOST COMMUNICATION W/LEFT SIDE SATELLITE ACCELERATION SENSOR 1

For a complete wiring diagram Refer to Section 8W.

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 code will set, if the ORC and the Left Side Impact Sensor 1 do not establish and maintain valid data communications.

Possible Causes

(R13) SIGNAL CIRCUIT SHORTED TO BATTERY

(R13) SIGNAL CIRCUIT SHORTED TO GROUND

(R13, R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS SHORTED TOGETHER

(R15) LEFT SIDE IMPACT SENSOR 1 GROUND CIRCUIT OPEN

(R13) LEFT SIDE IMPACT SENSOR 1 SIGNAL CIRCUIT OPEN

ORC, LEFT SIDE IMPACT SENSOR 1

Diagnostic Test

1. VERIFY THAT DTC U0172-LOST COMMUNICATION W/LEFT SIDE SATELLITE ACCELERATION SENSOR 1 IS ACTIVE

NOTE: Ensure the battery is fully charged.

Turn the ignition on.
With the scan tool, read ORC DTC.

Does the scan tool display active: U0172-LOST COMMUNICATION W/LEFT SIDE IMPACT SENSOR 1?

Yes

Go To 2

Go To 9

2. CHECK THE (R13) and (R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS FOR A SHORT TO BATTERY

WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.

Disconnect the Left Side Impact Sensor 1 connector.
Disconnect the ORC connectors.
Connect the ORC 8443-32-L Adaptor to the ORC connectors.

WARNING: To avoid serious or fatal injury, turn the ignition on, then reconnect the battery.

Measure the voltage of the (R13) Left Side Impact Sensor 1 Signal circuit and (R15) Sensor Ground circuit between the Left Side Impact Sensor 1 connector and ground.

Is there any voltage present?

Yes

WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.
Repair the (R13) and (R15) Left Side Impact Sensor 1 circuits for a short to battery.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

Go To 3

3. CHECK THE (R13) and (R15) LEFT SIDE IMPACT SENSOR 1 CIRCUITS FOR A SHORT TO GROUND

WARNING: To avoid serious or fatal injury, turn ignition on, then reconnect the battery.

Measure the resistance of the (R13) Left Side Impact Sensor 1 Signal circuit between the Left Side Impact Sensor 1 connector and ground.
Measure the resistance of the (R15) Left Side Impact Sensor 1 Ground circuit between the Left Side Impact Sensor 1 connector and ground.

Is the resistance below 100K ohms on either circuit?

Yes

WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.
Repair the (R13) and (R15) Left Side Impact Sensor 1 Signal and Ground circuit for a short to ground.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

Go To 4

4. CHECK THE (R13) and (R15) LEFT SIDE IMPACT SENSOR CIRCUITS FOR A SHORT TOGETHER

Measure the resistance between the (R13) Left Side Impact Sensor 1 Signal and (R15) Sensor Ground circuits at the Left Side Impact Sensor 1 connector.

Is the resistance below 100K ohms?

Yes

Repair the (R13) and (R15) Left Side Impact Sensor 1 circuits shorted together.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

Go To 5

5. CHECK THE (R15) LEFT SIDE IMPACT SENSOR 1 GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

Measure the resistance of the (R15) Left Side Impact Sensor 1 Ground circuit between the Left Side Impact Sensor 1 connector and the ORC 8443-32-L Adaptor.

Is the resistance below 1 ohm?

Yes

Go To 6

Repair the (R15) Left Side Impact Sensor 1 Ground circuit for an open or high resistance.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

6. CHECK THE (R13) LEFT SIDE IMPACT SENSOR 1 CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

Measure the resistance of the (R13) Left Side Impact Sensor 1 Signal circuit between the Left Side Impact Sensor 1 connector and the ORC 8443-32-L Adaptor.

Is the resistance below 1 ohm?

Yes

Go To 7

Repair the (R13) Left Side Impact Sensor 1 Signal circuit for an open or high resistance.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

7. CHECK OPERATION OF THE LEFT SIDE IMPACT SENSOR 1

Replace the Left Side Impact Sensor 1.
Reconnect the vehicle body harness to the impact sensor.
Remove any special tools or jumper wires and reconnect all previously disconnected components - except the Battery.

WARNING: To avoid serious or fatal injury, turn the ignition on, then reconnect the battery.

Connect the scan tool to the Data Link Connector - use the most current software available.
Use the scan tool and erase the stored codes in all airbag system modules.
Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
Wait one minute, and read active codes and if there are none present read the stored codes.

Did the active Left Side Impact Sensor 1 DTC return?

Yes

Go To 8

Repair is complete.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

8. REPLACE THE OCCUPANT RESTRAINT CONTROLLER

WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.

WARNING: If the airbag control module is dropped at any time, it must be replaced. Failure to take the proper precautions could result in accidental airbag deployment and serious or fatal injury.

If there are no possible causes remaining, view repair.

Repair

Replace the Occupant Restraint Controller in accordance with Service Instructions.
Perform the *AIRBAG SYSTEM VERIFICATION TEST - VER 1.

9. TEST FOR AN INTERMITTENT CONDITION

With the scan tool, record and erase all DTC from all Airbag modules.
If any ACTIVE codes are present they must be resolved before diagnosing any stored codes.

WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Look for chafed, pierced, pinched, or partially broken wires and broken, bent, pushed out, spread, corroded, or contaminated terminals.
The following additional checks may assist you in identifying a possible intermittent problem.
Reconnect any disconnected components and harness connector.

WARNING: To avoid serious or fatal injury, turn the ignition on, then reconnect the battery.

With the scan tool monitor active codes as you work through the following steps.

WARNING: To avoid serious or fatal injury, maintain a safe distance from all airbags while performing the following steps.

Wiggle the wiring harness and connectors of the related airbag circuit or component.
If codes are related to the Driver Airbag circuits, rotate the steering wheel from stop to stop.
If only stored codes return continue the test until the problem area has been isolated.
In the previous steps you have attempted to recreate the conditions responsible for setting active DTC in question.

Are any ACTIVE DTC present?

Yes

Select the appropriate symptom from Symptom List.

No problem found at this time. Erase all codes before returning vehicle to customer.