What it means
A receiving module detected implausible data from the left side restraints control module (side airbag/curtain controller). Side-impact sensor data fails plausibility checks and is rejected.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The left side restraints control module handles information for the vehicle's left-side airbag or curtain system and shares status with other modules. U0453 is set when a receiving module rejects implausible data attributed to that left-side controller; it identifies the left side and does not prove that the airbag itself is defective.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- Gateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan the SRS and other modules for U0453, related left-side restraint codes, and freeze-frame details to identify the receiver and event conditions.
- Check the SRS warning lamp and ask whether there has been recent work, impact, or water exposure near the left-side restraint system.
- With the ignition off and following the manufacturer's SRS safety procedure, inspect accessible left-side module connectors and harness routing for damage or disturbed connections.
- Use an SRS-capable scan tool to compare the left-side controller's reported status with other restraint data and check whether the right-side controller reports similar errors.
- If a left-side controller or related module was replaced, verify its software and configuration against manufacturer requirements.
- Use the manufacturer's diagnostic procedure to test the left-side controller and network path; do not probe airbag igniter circuits with a standard meter.
Common fixes
- Repair a loose, corroded, or damaged left-side controller connector or harness according to SRS service procedures.
- Correct software or configuration incompatibility after module replacement.
- Repair or replace a left-side sensor input or controller if testing confirms it is supplying implausible data.
- Repair a network or gateway fault if the data becomes invalid while being relayed.
Can I keep driving?
An SRS fault may leave left-side airbag or curtain protection unavailable or impaired, so arrange prompt diagnosis and drive cautiously. Do not assume the left-side restraints will operate normally in a side impact.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.