AutoCodes – Generic – U0177

U0177 Code - Lost Communication With Restraints System Sensor 'H'

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Restraints System Sensor 'H', Restraints System Sensor 'H' harness is open or shorted, Restraints System Sensor 'H' circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U0177 indicates Lost Communication With Restraints System Sensor 'H'.
Common causes: Common causes include Faulty Restraints System Sensor 'H', Restraints System Sensor 'H' harness is open or shorted, Restraints System Sensor 'H' circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,477

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0177 Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Restraints System Sensor 'H' has not been received.

OBDII Code U0177 - Lost Communication With Restraints System Sensor 'H' - AutoCodes.com — U0177 Code - Lost Communication With Restraints System Sensor 'H'

What does this mean?

What are the Possible Causes of the DTC U0177?

Faulty Restraints System Sensor 'H'
Restraints System Sensor 'H' harness is open or shorted
Restraints System Sensor 'H' circuit poor electrical connection

How to Fix the DTC U0177?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0177 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U0177 code?

Need more information on how to fix the U0177 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0177 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U0177 Chrysler — Lost Communication With Right Side Satellite Acceleration Sensor 3
U0177 Dodge — Lost Communication With Right Side Satellite Acceleration Sensor 3
U0177 Fiat — Lost Communication With Right Side Satellite Acceleration Sensor 3
U0177 Jeep — Lost Communication With Right Side Satellite Acceleration Sensor 3
U0177 RAM — Lost Communication With Right Side Satellite Acceleration Sensor 3

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U0177 Code

1. What are common symptoms of OBDII code U0177 (Lost Communication With Restraints System Sensor 'H')?

- Common symptoms include the airbag warning light illuminating on the dashboard, loss of communication with the restraint system sensor, and potential issues with the airbag system.

2. What are some possible causes of OBDII code U0177?

- Possible causes include a damaged or faulty restraint system sensor 'H', loose or corroded wiring connections, a blown fuse related to the airbag system, or a malfunctioning control module.

3. How can I diagnose the issue related to OBDII code U0177?

- Diagnosing the issue involves using an OBDII scanner to read the fault code, inspecting the wiring connections to the restraint system sensor 'H', checking the airbag system fuse, and performing a thorough visual inspection of the components.

4. Can driving with OBDII code U0177 pose any risks?

- Driving with this code may pose a risk as the airbag system may not function properly in the event of a collision, potentially leading to increased injury risk for the vehicle occupants.

5. What are some recommended repair tips for fixing OBDII code U0177?

- Repair tips include checking and repairing any damaged wiring connections, replacing the restraint system sensor 'H' if necessary, ensuring all fuses related to the airbag system are intact, and clearing the fault code with an OBDII scanner after repairs are completed.

6. Is it possible to reset OBDII code U0177 without fixing the underlying issue?

- While it is possible to clear the fault code temporarily, it is crucial to address the root cause of the communication loss with the restraint system sensor 'H' to ensure the proper functioning of the airbag system.

7. Can a DIY enthusiast fix OBDII code U0177 at home?

- Depending on the individual's automotive knowledge and skills, some DIY enthusiasts may be able to diagnose and repair the issue related to this code, especially if it involves checking wiring connections and replacing components like the sensor.

8. How long does it typically take to repair OBDII code U0177?

- The repair time can vary based on the specific cause of the communication loss, but in general, it may take anywhere from 1 to 3 hours to diagnose and fix the issue related to this code.

9. Are there any recalls related to OBDII code U0177 for specific vehicle models?

- It is recommended to check with the vehicle manufacturer or the National Highway Traffic Safety Administration (NHTSA) for any recalls related to this code, as some vehicle models may have known issues with the airbag system components.

10. What are the potential safety implications of ignoring OBDII code U0177?

- Ignoring this code can lead to the airbag system not deploying properly in the event of a collision, increasing the risk of injury to the vehicle occupants. It is crucial to address this issue promptly to ensure the safety of the vehicle's occupants.