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U183C Cadillac Code - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Hybrid/EV Powertrain Control Module 2 On Powertrain Expansion Communication Bus

Quick Answer

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Common causes include Faulty Hybrid/EV Powertrain Control Module 2, Hybrid/EV Powertrain Control Module 2 harness is open or shorted, Hybrid/EV Powertrain Control Module 2 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: U183C Cadillac indicates Auxiliary Transmission Fluid Pump Control Module Lost Communication With Hybrid/EV Powertrain Control Module 2 On Powertrain Expansion Communication Bus.
Common causes: Common causes include Faulty Hybrid/EV Powertrain Control Module 2, Hybrid/EV Powertrain Control Module 2 harness is open or shorted, Hybrid/EV Powertrain Control Module 2 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 551

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jun 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U183C Cadillac Description

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Once the scan tool is connected to the serial data circuit through the Data Link Connector (DLC), the scan tool can be used to monitor each device for diagnostic purposes and to check for Diagnostic Trouble Code (DTC). When the vehicle is ON, each device communicating on the serial data circuit sends a state of health message to ensure that the device is operating properly. When a device stops communicating on the serial data circuit, for example, if the device loses power or ground, the state of health message it normally sends on the serial data circuit disappears. Other devices on the serial data circuit, which expect to receive that state of the health message, detect its absence; those devices in turn set a DTC associated with the loss of the state of health of the non-communicating device. A loss of serial data communications DTC does not represent a failure of the devices that contain the stored DTC. The DTC will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U183C Cadillac - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Hybrid/EV Powertrain Control Module 2 On Powertrain Expansion Communication Bus - AutoCodes.com — U183C Cadillac Code - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Hybrid/EV Powertrain Control Module 2 On Powertrain Expansion Communication Bus

What does this mean?

What are the Possible Causes of the DTC U183C Cadillac?

Faulty Hybrid/EV Powertrain Control Module 2
Hybrid/EV Powertrain Control Module 2 harness is open or shorted
Hybrid/EV Powertrain Control Module 2 circuit poor electrical connection

How to Fix the DTC U183C Cadillac?

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 U183C Cadillac 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 U183C Cadillac Code

1. What does the OBDII code U183C mean on a Cadillac?

U183C indicates that the Auxiliary Transmission Fluid Pump Control Module has lost communication with Hybrid/EV Powertrain Control Module 2 on the powertrain expansion communication bus.

2. What are the common symptoms of a U183C code on a Cadillac?

Symptoms may include transmission performance issues, failure to engage gears, warning lights on the dashboard, or reduced vehicle performance.

3. What causes the U183C code to appear?

This code can be caused by faulty wiring or connectors, a failed Auxiliary Transmission Fluid Pump Control Module, a malfunctioning Hybrid/EV Powertrain Control Module 2, or software issues in the communication system.

4. Can a U183C code cause drivability issues?

Yes, it can lead to transmission performance problems and may cause the vehicle to enter limp mode to protect the drivetrain.

5. How can I diagnose a U183C code?

Start by inspecting the wiring and connectors between the Auxiliary Transmission Fluid Pump Control Module and Hybrid/EV Powertrain Control Module 2 for damage or corrosion. Use a diagnostic scan tool to check for related codes and perform communication tests.

6. Is it safe to drive with a U183C code?

Driving with this code can be risky as it may impact transmission operation and overall vehicle performance. Itâ€™s best to address the issue promptly.

7. How do I fix the U183C code on my Cadillac?

Repairs may involve fixing damaged wiring or connectors, replacing the Auxiliary Transmission Fluid Pump Control Module, updating software, or replacing the Hybrid/EV Powertrain Control Module 2 if necessary.

8. Can a software update resolve the U183C code?

In some cases, a software update to the control modules involved may resolve communication issues and clear the code.

9. What tools are needed to troubleshoot a U183C code?

Youâ€™ll need a diagnostic scan tool capable of reading manufacturer-specific codes, a multimeter for testing electrical circuits, and possibly the vehicleâ€™s service manual for wiring diagrams.

10. Does a U183C code require professional repair?

While basic inspections can be done at home, repairing communication issues or replacing control modules often requires professional expertise and advanced tools.