What Does C1868 Mean?
The air suspension rear inflator solenoid output circuit is shorted to ground. The control module detects that the solenoid circuit has an unintended path to ground, which prevents proper solenoid operation. The rear air springs will not inflate correctly, the vehicle rear will sag, and the suspension warning light will be illuminated.
Common Causes
35%
Chafed solenoid wiring contacting the vehicle frame, body, or other grounded metal surface
25%
Water intrusion into the solenoid connector creating a conductive path to ground through corrosion or standing water
20%
Internal solenoid coil short to ground (coil winding contacting the metal solenoid body/housing)
12%
Pinched harness at a body or frame pass-through point crushing the wire against a grounded surface
8%
Air suspension module output driver shorted to ground internally
Diagnostic Steps
1
Disconnect the solenoid connector. Measure resistance from each solenoid wire to chassis ground at the module-side connector. Readings below 100 ohms indicate a short to ground in the harness.
2
With the solenoid disconnected, measure coil resistance between the two solenoid terminals (should be 8-15 ohms) and from each terminal to the solenoid body/housing. Any low reading to the body indicates an internal ground short.
3
Inspect the harness from the solenoid to the module for areas where the wire contacts metal. Check at frame rail clips, axle mounts, and grommet pass-throughs. Look for worn-through insulation.
4
If the harness appears intact, disconnect the harness at any intermediate junction points and test each section independently to isolate the shorted segment.
5
Verify the module is not the source by disconnecting the harness at the module and measuring from the module output pin to ground. This should read open (infinite resistance) if the module is good.
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The air suspension rear inflator solenoid output circuit is shorted to ground. The control module detects that the solenoid circuit has an unintended path to ground, which prevents proper solenoid operation. The rear air springs will not inflate correctly, the vehicle rear will sag, and the suspensi...
The most common cause of C1868 (Air Suspension Rear Inflator Solenoid Output Circuit Short To Ground) is: Chafed solenoid wiring contacting the vehicle frame, body, or other grounded metal surface
Typical repair costs for C1868 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The rear suspension will not inflate properly, causing the vehicle to ride low in the rear. This affects handling, braking distribution, and headlight aim. The vehicle can be driven short distances at moderate speeds, but avoid heavy loads. The short to ground may also blow fuses if not corrected, potentially affecting other systems sharing the same circuit.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1868 to identify the root cause.
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Quick Info
Category
Chassis
System
Air Suspension
Difficulty
Type
Manufacturer
Recommended Tools
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