What Does C1905 Mean?
The ride control module has detected a circuit failure in the left rear shock actuator. The electronically controlled damper at the LR corner cannot be commanded, meaning the module has lost the ability to adjust damping firmness at that position. The shock will default to a fixed setting, and the system may disable adaptive ride control entirely on some vehicles.
Common Causes
35%
Failed LR shock actuator solenoid from internal coil degradation due to heat, vibration, and moisture exposure
30%
Damaged or deteriorated wiring between the ride control module and the LR shock actuator
25%
Corroded connector at the LR shock actuator from road environment exposure
10%
Ride control module internal output driver failure on the LR channel
Diagnostic Steps
1
Step 1: Measure LR shock actuator solenoid resistance at its connector (typical: 3-8 ohms). Compare to known-good specification.
2
Step 2: Verify module output to the LR actuator using an oscilloscope. The module should output a PWM control signal when the ride control system is active.
3
Step 3: Test wire continuity from actuator connector to module connector. Inspect harness for damage at suspension flex points.
4
Step 4: Inspect the actuator connector for corrosion, moisture, and terminal damage.
5
Step 5: Use bidirectional controls to command the actuator through its damping range. Listen for the characteristic click as damping modes change.
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
The ride control module has detected a circuit failure in the left rear shock actuator. The electronically controlled damper at the LR corner cannot be commanded, meaning the module has lost the ability to adjust damping firmness at that position. The shock will default to a fixed setting, and the s...
The most common cause of C1905 (Ride Control LR Shock Actuator Circuit Failure) is: Failed LR shock actuator solenoid from internal coil degradation due to heat, vibration, and moisture exposure
Typical repair costs for C1905 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A non-functional LR shock actuator causes asymmetric rear damping, which can result in uneven handling characteristics. The vehicle is driveable but may behave unpredictably on rough roads or during aggressive maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1905 to identify the root cause.
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Quick Info
Category
Chassis
System
Electronic Ride Control / Adaptive Suspension
Difficulty
Type
Manufacturer
Recommended Tools
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