AutoCodes – Generic – U0070

U0070 Code - Vehicle Communication Bus 'E' (-) Low

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module. 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: U0070 indicates Vehicle Communication Bus 'E' (-) Low.
Common causes: Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module.
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 5,693

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 Mar 29, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0070 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 supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U0070 - Vehicle Communication Bus 'E' (-) Low - AutoCodes.com — U0070 Code - Vehicle Communication Bus 'E' (-) Low

What does this mean?

What are the Possible Causes of the DTC U0070?

Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s)
Check for more codes
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0070?

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 U0070 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 U0070 code?

Need more information on how to fix the U0070 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0070 code diagnosed by a professional: Find a repair shop in your area

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 U0070 Code

1. What does the OBDII code U0070 mean?

U0070 indicates a low voltage issue on the Vehicle Communication Bus 'E' (-), which can disrupt communication between vehicle modules.

2. What are the common symptoms of a U0070 code?

Symptoms may include warning lights on the dashboard, failure of certain electronic systems, or intermittent communication errors.

3. What causes the U0070 code to appear?

Common causes include damaged wiring, loose or corroded connectors, a faulty control module, or a short circuit in the communication bus.

4. Can a weak battery cause the U0070 code?

Yes, a weak or failing battery can result in insufficient voltage, potentially triggering this code.

5. How do I diagnose the U0070 code?

Check the wiring and connectors for damage or corrosion, test the battery and charging system, and inspect the communication bus with a diagnostic scanner.

6. Can I drive my car with a U0070 code?

While the vehicle may still be drivable, ignoring the code can lead to communication failures and potentially affect critical systems.

7. How can I fix the U0070 code?

Repair or replace damaged wiring, clean or secure connectors, and update or reprogram faulty modules as needed.

8. What tools are needed to troubleshoot the U0070 code?

Youâ€™ll need an OBDII scanner, a multimeter for testing continuity and voltage, and possibly a wiring diagram for your vehicle.

9. Does a U0070 code always require professional repair?

Simple issues like loose connectors or battery problems can be fixed at home, but complex wiring or module issues may require professional assistance.

10. How much does it typically cost to repair a U0070 code?

Costs vary depending on the issue, but minor repairs like fixing a connector may cost under $100, while module replacements could exceed $500.