[SOLVED] U1821 Code: Fixing Lost Communication With Powertrain Expansion Bus

The automobile fault code U1821 indicates a problem with the 14V Power Module in your vehicle.

The most common symptom is the Engine Light turning on, which should not be ignored. The cause of this issue could be a faulty 14V Power Module, an open or shorted harness, or a poor electrical connection. It is important to visually inspect the wiring harness and connectors for any damage or corrosion.

The repair time for this issue is estimated to be around 1.0, and it is crucial to fix this problem as soon as possible to avoid further damage to your vehicle. To interpret the fault code, you can use an OBD-II scanner or take your car to a professional mechanic.

Repair Importance Level10.0 (Out of 10)
Estimated Repair TimeApproximately 1.0 hour
Repair Difficulty Level10.0 (Out of 10)

If you see the Engine Light ON or Service Engine Soon Warning Light, it could be due to the u1821 fault code.

Here are the symptoms to look out for:

  • The automobile fault code U1821 has the following symptoms: Engine Light ON, Service Engine Soon Warning Light ON.

The automobile fault code u1821 can be caused by a faulty power module, open or shorted harness, or poor electrical connection.

  • The automobile fault code U1821 can be caused by a faulty 14V Power Module.
  • It can also be caused by an open or shorted 14V Power Module harness.
  • Additionally, a poor electrical connection in the 14V Power Module circuit can also trigger this fault code.

Below are some possible fixes for the automobile fault code u1821, including inspecting wiring harness and connectors for damage or corrosion.

  • To fix the automobile fault code u1821, first, check the possible causes listed above.
  • Then, visually inspect the related wiring harness and connectors.
  • Look for any damaged components and check for broken, bent, pushed out, or corroded connector’s pins.
  • This fix will take an estimated repair time of 1.0 hour.

The automobile fault code U1821 has an estimated repair time of 1.0 hour. The cost of fixing this fault code is influenced by the repair time.

Most auto repair shops charge between $75 and $150 per hour for their services. Therefore, the fixing cost of U1821 will be between $75 and $150, depending on the repair time required.

It is important to consider the repair time and the hourly rate when estimating the fixing cost of this fault code.

The U1821 code is related to the powertrain high-speed General Motor Local Area Network (GMLAN) serial data circuits.

Devices connected to this network monitor for serial data communications during normal vehicle operation. The code is triggered when a supervised periodic message that includes the transmitter device availability has not been received.

Specifically, the U1821 code indicates that there is a lost communication with the 14V power module on the powertrain expansion communication bus.

What are the possible causes of the u1821 automobile fault code?

If you see the engine light on or the service engine soon warning light, it could be due to the u1821 fault code. This code is usually caused by a faulty 14V Power Module, an open or shorted 14V Power Module harness, or a poor electrical connection in the 14V Power Module circuit. To fix this issue, you should visually inspect the related wiring harness and connectors, check for damaged components, and look for broken, bent, pushed out, or corroded connector’s pins.

How can I visually inspect the related wiring harness and connectors to fix the u1821 fault code?

If you’re experiencing the u1821 fault code, which is indicated by the Engine Light ON or Service Engine Soon Warning Light, you can fix it by visually inspecting the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins. This fault code is usually caused by a faulty 14V Power Module, an open or shorted 14V Power Module harness, or a poor electrical connection in the 14V Power Module circuit.

What are the signs of damaged components or broken, bent, pushed out, or corroded connector’s pins that I should look for when fixing the u1821 fault code?

If you’re dealing with the u1821 fault code, keep an eye out for the engine light or service engine soon warning light turning on. The cause of this issue could be a faulty 14V Power Module, an open or shorted 14V Power Module harness, or a poor electrical connection in the 14V Power Module circuit. To fix this problem, check the possible causes listed above and visually inspect the related wiring harness and connectors. Be sure to look for damaged components and check for broken, bent, pushed out, or corroded connector’s pins.

u1821 error fault code explained

If your engine light is on, it could be due to a faulty 14V Power Module, an open or shorted harness, or poor electrical connection. Visually inspect the wiring harness and connectors for damage or corrosion.

Check for broken, bent, or pushed out pins.

Scroll to Top