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U0273 — Lost Communication Lighting Driver Control Module

Generic OBD-II · all makesNetwork / communication

U0273 means the powertrain or body control module can no longer communicate with the Lighting Driver Control Module over the CAN bus. This module typically manages LED headlamp, taillamp, or signature-light functions. When communication stops, the controller logs the code and the affected lighting features may degrade or fail.

Symptoms

What causes it — most likely first

1. Failed Lighting Driver Control Module

The module itself is the most common cause. Internal driver electronics, especially in LED lighting modules, can fail due to heat cycling, moisture intrusion, or internal circuit damage, causing it to drop off the CAN network.

2. Wiring or connector fault to the module

Open, shorted, pinched, or corroded power, ground, or data wires between the module and the vehicle harness interrupt both operation and communication. Connector pin damage from water entry is common in lighting assemblies.

3. CAN bus line fault

A break, short to power, short to ground, or excessive resistance on the CAN high or CAN low circuits prevents the module from exchanging data with the rest of the network.

4. Power or ground loss to the module

Missing battery voltage, ignition feed, or a poor ground to the lighting control module can keep it silent on the bus even if the wiring harness itself is intact.

5. Moisture or thermal damage in the lamp assembly

Water leaking into a headlamp or taillamp housing can damage the integrated driver module and its connector, leading to intermittent or permanent loss of communication.

6. Faulty PCM or BCM

Although sometimes suggested, a failed engine or body control module is an uncommon root cause for a single lost-communication code and should only be considered after the module, wiring, and bus circuits have been ruled out.

How it's diagnosed

  1. Confirm U0273 is present and document any additional U-codes to determine if the problem is isolated to one module or affects the entire network.
  2. Locate the Lighting Driver Control Module, disconnect it, and inspect the connector and harness for corrosion, bent pins, backed-out terminals, or obvious wire damage.
  3. With a scan tool or multimeter, verify the module has correct battery voltage, ignition feed, and a solid ground when the ignition is on.
  4. Check CAN bus voltage and continuity at the module connector; typical CAN high is near 2.5–3.5 V and CAN low near 1.5–2.5 V with the module disconnected, and continuity should exist to the network gateway or splice.
  5. If power, ground, and CAN wiring are correct but the module does not communicate or respond, replace the Lighting Driver Control Module.
  6. Consider PCM or BCM failure only if multiple unrelated modules are simultaneously dropping communication and all individual module circuits test normal.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make
Related codesU0270 — Lost Communication Image Processing SeU0271 — Lost Communication Seat Control SwitchU0272 — Lost Communication Seat Control SwitchU0274 — Lost Communication Lighting Driver ConU0275 — Lost Communication Lighting Driver ConU0276 — Lost Communication Lighting Driver Con

Frequently asked

Is it safe to keep driving with U0273?

The vehicle can usually be driven, but exterior lighting may not work correctly, which can create a safety or legal issue at night. You should have it diagnosed promptly.

Do I need to replace the PCM for U0273?

Usually not. For a single lost-communication code like U0273, the fault is most often the Lighting Driver Control Module itself, its wiring, or its connector. Replacing the PCM is rarely the correct fix.

Where is the Lighting Driver Control Module located?

It is commonly integrated into or mounted on a headlamp, taillamp, or central lighting assembly. Consult the service information for the specific vehicle to find the exact location.

Can a weak battery cause this code?

A weak battery or poor charging system can cause low-voltage communication faults, but it usually produces multiple random U-codes rather than only U0273. Low system voltage should still be ruled out before replacing parts.