Code
C1122
LAND ROVER
C — Chassis
isolation Steering valve
Views:
UK: 6
EN: 9
RU: 5
AI status
Completed
Completed
100%
Causes
- Faulty steering isolation valve (stuck, leaking, mechanically seized)
- Failed valve solenoid or actuator
- Open/short or intermittent wiring/connector to valve
- Poor power or ground to valve control circuit
- Contaminated or low hydraulic fluid / internal blockage
- Faulty steering control module (SCM) / ECU or corrupted software
Symptoms
- Steering warning lamp (SAS/ESP/traction) illuminated
- Reduced or intermittent power steering assist, heavy steering at low speeds
- Erratic steering assist changes with engine speed or load
- Diagnostic trouble code C1122 stored in fault memory
- Possible unusual steering noise or fluid leakage
- Related stability/ABS/traction warnings if modules share data
What to check
- Read and record all stored DTCs and freeze-frame data with a compatible diagnostic tool
- Check for additional steering/ABS/ESP/U-codes that indicate related faults
- Visual inspection of steering valve solenoid connector and wiring for corrosion, damage, pin push-out or water ingress
- Check fuses and relays supplying the steering valve/control module
- Inspect hydraulic reservoir fluid level and condition for contamination or discoloration
- Scan for live data: valve status, command/duty cycle, supply voltage, grounds and CAN message activity
Signal parameters
- Supply voltage to valve (key ON) — compare to battery voltage (expected ~12V nominal)
- Ground continuity at valve ground terminal
- Control signal (voltage or PWM duty cycle) from SCM when valve is commanded (record percent duty cycle or voltage range)
- Solenoid coil resistance (compare to factory specification)
- Command vs. feedback: valve command value from SCM and any valve position/pressure feedback reading
- Hydraulic pressure upstream/downstream of valve at idle and during assist demand (compare to spec)
Diagnostic algorithm
- Retrieve all stored and pending codes, note freeze-frame and clear codes. Re-scan to confirm repeatability of C1122.
- Perform visual inspection: connectors, wiring harness along steering rack, fuses, relays and hydraulic lines for damage or contamination.
- With key ON, verify battery voltage at valve supply pin and check ground continuity to chassis ground. Repair any supply/ground issues.
- Measure solenoid coil resistance and compare to factory spec. If open/short, replace valve/solenoid per manufacturer guidance.
- Use a diagnostic tool to command the isolation valve while observing command signal (voltage/PWM) and any live pressure/position feedback. Confirm valve response (you may hear or feel actuation).
- Check hydraulic pressures upstream and downstream of the valve with a calibrated gauge while commanding valve open/closed. Look for pressure loss, restricted flow, or internal leakage.
- Inspect hydraulic fluid for contamination; flush or replace fluid and filter if contaminated. Replace valve if mechanical contamination has damaged internals.
- If electrical signals are correct and valve does not respond, replace valve assembly. After replacement, clear codes and perform steering calibration/relearn procedures per service manual.
- If valve and hydraulic system test good but code persists, inspect SCM/ECU and CAN communications; check for software updates or module faults and consider module testing or reprogramming.
- Road-test vehicle to confirm restored assist and verify no recurrence of C1122.
Likely causes
- Valve solenoid electrical fault (open/short/intermittent connector)
- Valve mechanically stuck from contamination or internal wear
- Loss of power/ground to the valve circuit
- Connector corrosion or damaged wiring harness near steering gear
- Hydraulic contamination or low fluid level causing valve sticking
Fault status
Status
C1122 — Steering isolation valve fault detected. Steering assist may be reduced or unavailable; service the isolation valve circuit and related hydraulic systems.
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
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