What Does C1766 Mean?
The rear air suspension height sensor low-range signal circuit is open. No signal is reaching the control module from this sensor, indicating a disconnected plug, broken wire, or open sensor element.
Common Causes
35%
Disconnected sensor connector
30%
Broken wire in the signal circuit due to flex fatigue near the rear axle
20%
Open circuit inside the height sensor
15%
Corroded terminal with intermittent open
Diagnostic Steps
1
Step 1: Verify the sensor is plugged in and the connector lock is engaged.
2
Step 2: Test signal wire continuity from the sensor to the module connector.
3
Step 3: Inspect harness routing near the rear axle for wire fatigue breaks, especially at flex points.
4
Step 4: Bench-test the sensor with an external 5V supply to confirm signal output.
5
Step 5: Repair the open wire or replace the sensor, clear codes, and calibrate.
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The rear air suspension height sensor low-range signal circuit is open. No signal is reaching the control module from this sensor, indicating a disconnected plug, broken wire, or open sensor element.
The most common cause of C1766 (Air Suspension Rear Height Sensor Low Signal Circuit Open) is: Disconnected sensor connector
Typical repair costs for C1766 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Rear fine-level adjustment is offline. Vehicle is drivable but may not level correctly under load. Repair at earliest convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1766 to identify the root cause.
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Quick Info
Category
Chassis
System
Air Suspension System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
