What Does U0170 Mean?
The control module has lost communication with restraint system sensor A, typically a side impact sensor or front crash sensor. This indicates a breakdown in the vehicle's CAN bus network communication specific to this sensor node.
Safety Warning
Airbag system may not deploy properly or at all in a collision. Vehicle should not be driven until repaired as occupant protection is compromised.
Common Causes
35%
Faulty or damaged impact sensor A (connector corrosion, water intrusion, or internal sensor failure)
30%
Damaged or broken wiring harness between sensor A and airbag control module
20%
Poor ground connection at sensor A mounting point or harness ground
10%
Airbag control module internal failure or communication circuit fault
5%
CAN bus termination resistor failure or bus short/open circuit
Diagnostic Steps
1
Step 1: Verify sensor A location using wiring diagrams (typically front or side impact sensor) and visually inspect sensor and connector for damage, corrosion, or water intrusion
2
Step 2: Check voltage supply and ground at sensor A connector using multimeter (typically 5V reference and good ground)
3
Step 3: Measure resistance on CAN bus lines between sensor A and airbag module (should be 60-120 ohms depending on network configuration)
4
Step 4: Inspect wiring harness routing for pinched, chafed, or damaged wires, especially near mounting points and body seams
5
Step 5: If all wiring and power/ground checks pass, substitute sensor A with known-good component to verify sensor failure
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The control module has lost communication with restraint system sensor A, typically a side impact sensor or front crash sensor. This indicates a breakdown in the vehicle's CAN bus network communication specific to this sensor node.
The most common cause of U0170 (Lost Communication With Restraints System Sensor A) is: Faulty or damaged impact sensor A (connector corrosion, water intrusion, or internal sensor failure)
Typical repair costs for U0170 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Airbag system may not deploy properly or at all in a collision. Vehicle should not be driven until repaired as occupant protection is compromised.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0170 to identify the root cause.
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Quick Info
Category
Network
System
Supplemental Restraint System (SRS/Airbag)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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