C1920 — Led #1 Circuit Failure

C1920 — Led #1 Circuit Failure. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: open or shorted wiring in the circuit, blown fuse feeding the circuit, control module driver fault.

chassis (brakes/steering/suspension)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm C1920 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many C0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the led #1 circuit for damage, corrosion, chafing or poor contact.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm C1920 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for C1920 (parts and labor, USD, independent shop rates): Control module repair: $300–$1,000; Repair wiring or connectors: $80–$250; Replace the faulty sensor or actuator: $150–$500. Overall, fixing C1920 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What are the symptoms of C1920?

Drivers most often notice: increased fuel consumption in some cases, the affected system operates intermittently or not at all, possible limp mode depending on the affected component, Check Engine Light on.

What is the most common cause of C1920?

The most common causes are: open or shorted wiring in the circuit, blown fuse feeding the circuit, control module driver fault.

Will C1920 clear itself?

Sometimes C1920 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What does OBD2 code C1920 mean?

Is it safe to drive with C1920?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

When your vehicle's control module detects a problem with one of the sensor or actuator circuits it manages, it logs a specific trouble code to help technicians pinpoint the issue. Code C1920 appears when the onboard diagnostics notice unexpected behavior in a circuit responsible for an LED indicator, classified under the chassis category, which encompasses braking, steering, and suspension systems. The official description for this code is "Led #1 Circuit Failure," referring to a primary lighting or indicator circuit that isn't functioning as the engine control unit expects.

The engine control unit (ECU) or body control module continuously monitors voltage and resistance values in these circuits against factory-calibrated thresholds. When readings fall outside acceptable ranges — either too high, too low, or erratic — the module stores C1920 and illuminates the check engine light. Most manufacturers require the condition to persist across multiple drive cycles before confirming a fault, which helps prevent false triggers from temporary electrical fluctuations. When C1920 is stored, the module also captures a freeze frame snapshot recording engine speed, load, coolant temperature, and vehicle speed at the exact moment the failure occurred. Reviewing this data first can dramatically speed up your diagnosis.

Symptoms of C1920

The check engine light or warning indicator activates on the dashboard
The affected LED or lighting circuit may flicker, operate intermittently, or fail completely
Some vehicles enter a reduced-power limp mode depending on which system is affected
Fuel economy may decrease slightly in certain driving conditions
The specific system controlled by the failed circuit operates abnormally or stops working

Common Causes of C1920

The most frequent culprits behind C1920 are electrical connection problems rather than component failures:

Corrosion, looseness, or physical damage at the connector housing for the LED circuit
Wiring that has become chafed, broken, or completely severed somewhere along the harness
A blown fuse that supplies power to the affected circuit
An internal driver fault within the control module itself responsible for controlling the LED

Less commonly, moisture intrusion or vibration stress over time can degrade connections without obvious visible damage.

Diagnosing C1920

Follow these steps to systematically track down the root cause of C1920:

Connect an OBD2 scanner and retrieve all stored codes. Save the freeze frame data associated with C1920 — note the engine conditions recorded when the fault was detected, as this helps recreate the failure scenario during testing.
Look for any related diagnostic trouble codes that may point toward a broader electrical issue. Check manufacturer technical service bulletins for your specific make and model — some C1920 conditions have documented factory fixes or require software updates rather than physical repairs.
Perform a thorough visual inspection of the wiring harness and connectors tied to the affected LED circuit. Look for frayed insulation, broken strands, corrosion buildup, or connectors that aren't fully seated.
Use a multimeter to check reference voltage, ground integrity, and signal continuity at the component connector while referencing factory specifications.
Conduct a wiggle test on the harness while monitoring live data — any signal dropouts or interruptions indicate a broken wire or loose connection that moves under vibration.
Clear the code after repairs, then drive the vehicle through a complete drive cycle including the conditions present in the freeze frame data. Confirm C1920 does not reappear before considering the repair complete.

Repair Options for C1920

Address the most likely and least expensive causes before considering component replacement:

Repair wiring or connectors: $80–$250
Replace the faulty sensor or actuator: $150–$500
Control module repair or replacement: $300–$1,000

Total Repair Cost for C1920

Your actual cost depends entirely on which part of the circuit has failed. Based on typical independent shop labor rates in the United States, expect to pay between $80 and $250 if simple wiring or connector repair resolves the issue. Sensor or actuator replacement runs $150 to $500 in most cases. The highest expense scenario involves the control module itself, ranging from $300 to $1,000 depending on whether repair or full replacement is necessary. Always pursue proper diagnosis before purchasing parts — the most expensive fix is rarely the first thing to try.

Can You Drive with C1920?

Most vehicles remain drivable when C1920 is active, though you may notice reduced functionality from the affected auxiliary system or minor performance changes. Prioritize getting this code investigated at your earliest convenience. If the failure causes stalling, prevents starting, or triggers brake or steering warning lights, treat the situation as urgent and have the vehicle transported to a repair facility rather than driving it.