AutoCodes – RAM – U029D RAM

U029D RAM Code - Lost Communication With NOX Sensor 'A'

Quick Answer

The aftertreatment system is equipped with two NOx Sensors and modules. Common causes include Low Battery Voltage, Faulty Nitrogen Oxide (NOx) Sensor Bank 'A', Nitrogen Oxide (NOx) Sensor Bank 'A' harness is open or shorted. 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: U029D RAM indicates Lost Communication With NOX Sensor 'A'.
Common causes: Common causes include Low Battery Voltage, Faulty Nitrogen Oxide (NOx) Sensor Bank 'A', Nitrogen Oxide (NOx) Sensor Bank 'A' harness is open or shorted.
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 4,819

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U029D RAM Description

The aftertreatment system is equipped with two NOx Sensors and modules. The upstream NOx Sensor 1/1 is located on the Turbocharger elbow downpipe and is permanently connected to a corresponding NOx Sensor Module mounted to the hot side of the engine block. The downstream NOx Sensor 1/2 is located at the outlet of the SCR Catalyst and is permanently connected to a corresponding NOx Sensor Module which is mounted on the right frame rail. The NOx Sensors and NOx Sensor Modules are calibrated to each other and must be replaced as an assembly. The two NOx Sensor and Module assemblies are not interchangeable. The NOx Sensor Modules are smart devices and communicate with the Powertrain Control Module (PCM) over the J1939 Data Link. The NOx Sensor Modules perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst and dosing system. The PCM will illuminate the Malfunction Indicator Lamp (MIL) after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL immediately after the monitor runs and passes.

OBDII Code U029D RAM - Lost Communication With NOX Sensor 'A' - AutoCodes.com — U029D RAM Code - Lost Communication With NOX Sensor 'A'

What does this mean?

What are the Possible Causes of the DTC U029D RAM?

Low Battery Voltage
Faulty Nitrogen Oxide (NOx) Sensor Bank 'A'
Nitrogen Oxide (NOx) Sensor Bank 'A' harness is open or shorted
Nitrogen Oxide (NOx) Sensor Bank 'A' circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC U029D RAM?

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 U029D RAM 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.

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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 U029D RAM Code

1. What are the common symptoms of OBDII code U029D related to Lost Communication With NOX Sensor 'A'?

The common symptoms include the check engine light being illuminated on the dashboard, decreased fuel efficiency, and potential performance issues.

2. What are some possible causes of OBDII code U029D indicating Lost Communication With NOX Sensor 'A'?

Possible causes may include a faulty NOX sensor 'A', damaged wiring or connectors, a software issue, or a problem with the powertrain control module (PCM).

3. How can I diagnose the issue related to OBDII code U029D?

Diagnosis typically involves using an OBDII scanner to retrieve the code and then conducting a thorough inspection of the NOX sensor 'A', its wiring, and related components for any signs of damage or malfunction.

4. Can driving with OBDII code U029D present any risks?

Driving with this code may not pose immediate dangers, but it can lead to increased emissions, reduced fuel efficiency, and potential long-term damage to the vehicle's emissions system if left unresolved.

5. Is it possible to reset the OBDII code U029D without fixing the underlying issue?

While clearing the code may temporarily turn off the check engine light, the issue causing the code will persist, and the code is likely to reappear until the root cause is addressed.

6. Are there any DIY repair tips for OBDII code U029D related to Lost Communication With NOX Sensor 'A'?

DIY repair tips include checking for loose or damaged wiring, ensuring proper sensor connections, and consulting the vehicle's service manual for specific troubleshooting steps.

7. How much does it typically cost to repair OBDII code U029D?

The cost of repair can vary depending on the exact cause of the issue, but it may range from a simple wiring repair to a sensor replacement or PCM reprogramming, potentially costing anywhere from $100 to $500 or more.

8. Can I continue driving my vehicle with OBDII code U029D until I can get it repaired?

While driving with this code may be possible, it is recommended to address the issue promptly to prevent further complications and ensure optimal vehicle performance and emissions compliance.

9. Will fixing OBDII code U029D require a visit to a mechanic or dealership?

Depending on your level of automotive expertise and the complexity of the repair, you may be able to address the issue yourself. However, consulting a mechanic or dealership is advisable for accurate diagnosis and professional repairs.

10. How can I prevent OBDII code U029D from occurring in the future?

Regularly maintaining your vehicle, following recommended service schedules, and addressing any underlying issues promptly can help prevent the recurrence of this code and other related problems.