U1816 Cadillac Code - Lost Communication With Drive Motor Control Module B On Bus B
Quick Answer
Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Drive Motor Control Module B, Drive Motor Control Module B harness is open or shorted, Drive Motor Control Module B 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
- U1816 Cadillac indicates Lost Communication With Drive Motor Control Module B On Bus B.
- Common causes
- Common causes include Faulty Drive Motor Control Module B, Drive Motor Control Module B harness is open or shorted, Drive Motor Control Module B 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.
Code U1816 Cadillac Description
The Diagnostic Trouble Code (DTC) will set when a supervised periodic message that includes the transmitter device availability has not been received.
What are the Possible Causes of the DTC U1816 Cadillac?
- Faulty Drive Motor Control Module B
- Drive Motor Control Module B harness is open or shorted
- Drive Motor Control Module B circuit poor electrical connection
How to Fix the DTC U1816 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 U1816 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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Frequently Asked Questions about U1816 Cadillac Code
1. What does the OBDII code U1816 mean on a Cadillac?
U1816 indicates a "Lost Communication With Drive Motor Control Module B On Bus B," meaning the vehicle's ECU has lost contact with the secondary drive motor control module over a specific communication network.
2. What are the common symptoms of code U1816 on a Cadillac?
Common symptoms include illuminated warning lights like the check engine light, reduced vehicle performance, potential stalling, or issues with hybrid or electric drive systems.
3. What causes the U1816 code to appear on a Cadillac?
Possible causes include faulty wiring or connectors, a malfunctioning drive motor control module B, communication bus issues, or software glitches in the ECU.
4. Can a loose connection trigger the U1816 code?
Yes, a loose or corroded connection in the communication circuit can disrupt the signal and trigger this code.
5. How do you diagnose the U1816 code on a Cadillac?
Diagnosis involves scanning for additional codes, inspecting wiring and connectors for damage, and testing the communication network and drive motor control module using specialized diagnostic tools.
6. Can the U1816 code cause drivability issues?
Yes, depending on the extent of the communication failure, it may result in reduced power, limited driving range, or the vehicle entering a limp mode.
7. Is it safe to drive with the U1816 code on a Cadillac?
Driving with this code may not be safe, as it could lead to unpredictable vehicle performance or a sudden loss of power. It's best to address the issue promptly.
8. How can the U1816 code be fixed on a Cadillac?
Repairs may include repairing or replacing damaged wiring, reconnecting loose connectors, reprogramming the ECU, or replacing the drive motor control module B.
9. How much does it cost to repair the U1816 code on a Cadillac?
Repair costs vary depending on the root cause, ranging from $100 for simple wiring fixes to over $1,000 if the drive motor control module needs replacement.
10. Can a software update resolve the U1816 code on a Cadillac?
In some cases, a software update for the ECU or related modules can resolve communication issues and clear the U1816 code.
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