Code
P1107
SUBARU
P — Powertrain
AIR System Diagnosis Solenoid Circuit Fault
Views:
UK: 38
EN: 54
RU: 47
AI status
Completed
Completed
100%
Causes
- Open or short in AIR solenoid wiring or connector
- Failed AIR system solenoid (stuck or coil open/short)
- Blown fuse or faulty relay supplying the AIR solenoid
- Poor ground at solenoid or PCM
- Corroded or loose connector pins
- PCM control output fault
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Failed emissions test (increased HC on cold start)
- Rough or unstable cold idle or poor cold-start driveability
- Secondary air injection not operating or audible air pump/valve noises absent
- Possible stored related codes (AIR system or emissions faults)
What to check
- Retrieve freeze frame and live data with a scan tool; note when code sets and related codes
- Visual inspection of AIR solenoid, connector, wiring harness, vacuum/air hoses and check valve
- Check fuses and relays that supply the AIR solenoid
- Back-probe solenoid connector to verify battery voltage, ground, and PCM control signal while commanding the solenoid
- Measure solenoid coil resistance with an ohmmeter
- Perform continuity checks between solenoid connector and PCM connector pins
Signal parameters
- Solenoid coil resistance: typically ~5–40 ohms (vehicle-specific — consult service manual)
- Battery feed to solenoid (when present): ~11–14.5 V with ignition ON
- PCM control output (low-side switch): Off ~12 V, On ~0–1 V (when switching to ground)
- When PWM controlled: duty cycle may vary 0–100%; measure with scope for waveform and frequency
- Intermittent/open circuit: infinite resistance or OL on coil or open continuity to PCM
- Short to ground: near 0 ohms to ground on wiring when ignition off (verify with meters)
Diagnostic algorithm
- Connect scan tool. Read and record P1107 and any related codes and freeze frame data. Verify key-on/engine-run conditions when code set.
- Perform visual inspection: check solenoid, connector, wire insulation, clamps, and AIR hoses/one‑way check valve for damage or disconnection.
- Check fuses/relays for the AIR system and replace if blown. Verify battery voltage at the solenoid power pin with ignition ON.
- Back-probe the solenoid connector. With ignition ON and engine OFF, measure voltage on the power circuit and reference (ground) pin.
- Command the AIR solenoid ON using a scan tool while monitoring the control pin voltage. Confirm the control pin changes (to near 0V if low‑side switched) or observe PWM waveform with a scope.
- Measure coil resistance at the solenoid connector (unplugged). Compare to expected range. If open or shorted, replace the solenoid.
- Check continuity between the solenoid connector and the PCM connector for power, control, and ground circuits. Repair any open/high resistance circuits.
- If voltage present but solenoid does not actuate, bench-test the solenoid by applying fused 12 V directly to verify mechanical operation. Replace if no response or intermittent.
- Repair/replace damaged wiring, corroded connectors, fuses, or solenoid as required. Reassemble and clear codes, then retest operation and road test to confirm code does not return.
- If wiring and solenoid verify good but code persists, consult OEM PCM diagnostics — suspect PCM driver fault and perform advanced tests or module replacement as directed by manufacturer procedures.
Likely causes
- Damaged harness between PCM and AIR solenoid (chafing, pinched, rodent damage)
- Corroded or water-intruded solenoid connector
- Failed solenoid coil (open or shorted)
- No battery feed to solenoid due to blown fuse/relay
- High resistance ground or poor mating at ground terminal
- Intermittent PCM driver or internal PCM fault (less common)
Fault status
Status
AIR system solenoid circuit fault — PCM detected abnormal electrical condition on the secondary air injection solenoid circuit.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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