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C1121 — Solenoid damper

Detailed page for trouble code C1121.

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Code

C1121

LAND ROVER C — Chassis

Solenoid damper

Brand: LAND ROVER
Views: UK: 7 EN: 10 RU: 3
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Page language: EN

Causes

  • Failed or internally shorted damper solenoid
  • Open or shorted wiring harness to the solenoid
  • Corroded, loose or contaminated connector or terminal
  • Poor ground or supply voltage to the solenoid circuit
  • Faulty suspension/air suspension control module or driver transistor
  • Software/firmware anomaly or calibration error

Symptoms

  • Suspension/systems warning lamp or message on instrument panel
  • Reduced or no active damping control; harsh or soft ride
  • Uneven ride height or poor vehicle stability/handling
  • Stored fault(s) in suspension control module
  • Vehicle may enter reduced-performance or limp mode for suspension
  • Noise from damper area if mechanical seizure present

What to check

  • Read and record all fault codes and freeze-frame data with a capable scan tool
  • Visually inspect damper solenoid connector(s), wiring harness and nearby harness routing for damage, corrosion or water ingress
  • Check fuses/relays related to suspension or damper circuits
  • Check battery voltage and good chassis battery ground before testing circuits
  • Back-probe the solenoid connector while commanding the solenoid with an appropriate diagnostic tool
  • Compare live data/command state vs actual solenoid signal using a scope or scan-tool data stream

Signal parameters

  • Supply voltage to solenoid: should be near battery voltage when supply feed is present (check against manufacturer spec)
  • Control signal: typically a PWM-driven driver from the suspension control module — duty cycle varies with commanded damping; frequency varies by system (check manufacturer values)
  • Solenoid coil resistance: must be within manufacturer specification (commonly single-digit to low tens of ohms); an open or near-zero reading indicates open/short condition
  • Continuity: low resistance path to ground/switching transistor when commanded should be present; check for intermittent resistance changes

Diagnostic algorithm

  1. Connect a full-function scan tool, read and save all stored and pending codes and freeze-frame data; note any related codes (ABS, ESC, communication).
  2. Visually inspect the affected damper(s), connectors and harness for corrosion, damage, water ingress or mechanical damage. Repair any obvious issues.
  3. Verify battery voltage and chassis ground. Replace or tighten poor battery/ground connections before further testing.
  4. Check fuses/relays for continuity and proper operation. Replace if faulty.
  5. With ignition on, back-probe the damper solenoid connector: verify supply voltage, ground reference and that the control signal changes when the SCM commands damping changes. Use an oscilloscope if available to confirm PWM characteristics.
  6. Measure solenoid coil resistance at the connector (unplugged from module). Compare to manufacturer spec. Replace solenoid if open, shorted or out of range.
  7. Check continuity between the solenoid connector and suspension control module pins to rule out harness opens/shorts. Wiggle test while monitoring for intermittent faults.
  8. If wiring and solenoid are good, verify that the suspension control module is receiving commands and is able to drive other outputs. Check for related communication codes (e.g., U0xxx).
  9. If module output is absent but input commands are present, suspect module driver fault — consider module repair or replacement following manufacturer procedures. Reprogram or calibrate module after replacement if required.
  10. After repairs, clear codes and perform road or system tests to confirm fault does not return and that damping behavior is restored.

Likely causes

  • Damper solenoid coil open or shorted
  • Damaged wiring or connector corrosion at the damper
  • Intermittent ground or low supply voltage to the solenoid
  • Faulty suspension control module output stage

Fault status

⚠️ Status
C1121 — Solenoid damper: Suspension control has detected an electrical or functional fault in the damper solenoid/circuit. May result in reduced or lost active damping control and a suspension fault warning.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 - 3.0 hours

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