Code
C0080
OPEL
C — Chassis
Rear Left Inlet Solenoid Valve Circuit Malfunction
Views:
UK: 2
EN: 6
RU: 2
AI status
Completed
Completed
100%
Causes
- Open or short in the rear-left inlet solenoid wiring (broken conductor, chafing)
- Corroded or disconnected connector at the solenoid or hydraulic unit
- Failed inlet solenoid valve (coil open or shorted)
- Faulty ground or poor battery/ignition supply to the ABS modulator
- Faulty ABS/ESP hydraulic control unit (internal driver failure)
- Blown fuse or faulty relay in the ABS power/ignition feed
Symptoms
- ABS and/or ESP/Traction control warning lamp illuminated
- Reduced or disabled ABS modulation on rear-left wheel
- Possible ABS fault message or reduced braking stability under heavy braking
- Related DTCs for other ABS solenoids or hydraulic unit may be present
- No obvious brake pedal feel change in normal braking (until ABS required)
What to check
- Read all stored ABS/ESP DTCs and freeze-frame data with a capable scan tool
- Visual inspection of wiring and connectors at the rear-left wheel and hydraulic unit
- Check ABS-related fuses and relays for continuity and proper operation
- Verify battery voltage is within normal range (engine off and running) before testing
- Attempt to actuate valves using a diagnostic tool (if supported) while observing responses
Signal parameters
- Supply voltage to hydraulic unit: battery voltage (~12–14.5 V) on power feed
- Control signal: typically a switched ground/PWM from ABS module to solenoid (varies by model)
- Solenoid coil resistance: low ohms range (typically several to a few tens of ohms) — compare with factory spec
- Open circuit = infinite resistance; short to ground or battery = near 0 ohms or excessive current
- When commanded, a PWM duty/frequency may be present on the control pin (use oscilloscope to confirm)
Diagnostic algorithm
- Connect a diagnostic scanner, record C0080 and related codes, and note freeze-frame/live data.
- Perform a visual inspection: check connectors to the hydraulic modulator, wiring harness routing, chafing, heat or corrosion signs.
- Check ABS fuses/relays and verify battery voltage at ignition on.
- Unplug the rear-left solenoid connector (or the hydraulic unit connector if serviceable) and inspect pins for corrosion or damage.
- Measure coil resistance across solenoid terminals (with battery disconnected). Compare to manufacturer spec; open or short indicates defective solenoid.
- With connector connected and ignition ON, backprobe the supply and control pins: verify constant supply voltage on power pin and observe control signal on control pin while commanding the valve via scan tool.
- If no control signal, trace continuity between ABS module and solenoid connector; check for shorts to ground or battery.
- Wiggle test wiring while commanding valve to reproduce intermittent faults. Use an oscilloscope to confirm PWM characteristics if available.
- If wiring and connector are good but solenoid is out of spec, replace the solenoid or hydraulic modulator as required per service manual.
- After repair, clear codes and perform a road test / ABS self-test to confirm fault does not return.
- Safety note: when servicing ABS hydraulic unit, follow manufacturer procedures to avoid introducing air into the brake system; bleed brakes if hydraulic components are replaced.
Likely causes
- Damaged wiring harness to rear-left inlet solenoid (most common)
- Corroded connector pins at the hydraulic modulator
- Defective solenoid coil inside the hydraulic unit
- Intermittent connection due to loose terminal or connector
- Internal driver transistor failure in ABS control module
Fault status
Status
Rear left inlet solenoid valve circuit malfunction detected by ABS/ESP control module — open, short, or loss of control to the solenoid.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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