What Does C1891 Mean?
The air suspension module has detected a short-to-battery condition on the left front height sensor signal circuit. A voltage source is feeding into the signal wire, causing the module to see an abnormally high voltage reading. The LF height data is invalid, and the module may misinterpret the corner height, potentially causing incorrect air spring inflation commands.
Common Causes
40%
Chafed signal wire contacting a power feed wire in the shared harness bundle near the LF suspension
30%
Internal sensor failure with signal line shorted to the 5V reference inside the sensor housing
20%
Contaminated connector with conductive debris or corrosion bridging signal to power pins
10%
Module internal circuit fault on the LF height sensor input
Diagnostic Steps
1
Step 1: Disconnect the LF height sensor and measure signal pin voltage at the connector (key on). Voltage dropping to near 0V indicates an internal sensor short; voltage remaining high points to wiring.
2
Step 2: With sensor disconnected, measure resistance from the signal wire to battery positive and to the 5V reference wire to identify the short source.
3
Step 3: Inspect the harness for abrasion, pinching, or aftermarket wire taps that could short the signal to a voltage source.
4
Step 4: Examine both connectors for bent or bridged pins, moisture, and conductive contamination.
5
Step 5: Replace the faulty component, verify a proper signal sweep through full travel, and clear codes.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The air suspension module has detected a short-to-battery condition on the left front height sensor signal circuit. A voltage source is feeding into the signal wire, causing the module to see an abnormally high voltage reading. The LF height data is invalid, and the module may misinterpret the corne...
The most common cause of C1891 (Air Suspension LF Height Sensor Circuit Short To Battery) is: Chafed signal wire contacting a power feed wire in the shared harness bundle near the LF suspension
Typical repair costs for C1891 range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A high-voltage height sensor fault can cause the system to over-deflate the LF air spring, creating a dangerous front-end sag on the left side that severely impacts steering response and braking stability.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1891 to identify the root cause.
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Quick Info
Category
Chassis
System
Air Suspension System
Difficulty
Type
Manufacturer
Recommended Tools
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