Code
P1171
DAEWOO
P — Powertrain
ETS VALVE STUCK - OPEN
Views:
UK: 1
EN: 11
RU: 3
AI status
Completed
Completed
100%
Causes
- Mechanical seizure of ETS valve (carbon/deposit buildup)
- Failed ETS actuator (motor or stepper)
- Broken or seized linkage or valve shaft
- Faulty ETS position feedback sensor
- Wiring or connector faults (open, short to voltage/ground, corrosion)
- Vacuum supply failure or leak (on vacuum-actuated designs)
Symptoms
- Check Engine/MIL illuminated
- Rough idle or unstable idle speed
- Reduced engine performance or hesitation
- Poor fuel economy and increased emissions
- Possible failed emissions test
- Engine surging or stalling at low load
What to check
- Read and record freeze frame data and all stored DTCs with a scan tool
- Visual inspection of ETS valve, linkage, vacuum lines and electrical connector for damage, contamination or corrosion
- With scan tool, command ETS valve and observe actuator response and position PID
- Check for power and ground at ETS connector with key ON (see service manual for pins)
- Measure position sensor voltage while moving the valve (voltage should change smoothly)
- Inspect related vacuum hoses for cracks, disconnections or blockages (if applicable)
Signal parameters
- Position sensor output should vary smoothly across its travel (typical range ~0.5–4.5 V) as valve moves; abrupt jumps indicate sensor or wiring fault
- Actuator supply should be present when commanded (approx battery voltage at supply pin with key ON/commanded)
- Control signal duty cycle or step commands should change when scanned/commanded
- Actuator coil/stepper resistance should match manufacturer spec — compare to service manual
- No excessive noise or intermittent dropouts in position feedback when commanded
Diagnostic algorithm
- Connect a capable scan tool and retrieve P1171 plus any other codes and freeze frame data. Note engine conditions when the code set.
- Visually inspect ETS valve, mounting, linkage, connectors and associated vacuum hoses. Repair obvious issues before further testing.
- Use the scan tool to command the ETS valve closed and open while monitoring the valve position PID and engine response. If it responds correctly, check for intermittent faults and re-test after warm-up.
- If no movement when commanded, check for power and ground at the ETS connector. If no supply, trace wiring back to fuse/relay and PCM; repair open/short as required.
- If power/ground are present but valve does not move, disconnect connector and measure actuator resistance and position sensor signals per service manual. Replace actuator if out of spec.
- If actuator moves but position PID shows it stuck open, remove ETS valve assembly and inspect for carbon, foreign material or seized linkage. Clean or replace as required.
- If vacuum-actuated, verify vacuum source and check for leaks or blocked lines. Replace hoses or vacuum solenoid as needed.
- If wiring and actuator check good but ECU still reports stuck open, perform PCM output/ground tests and consider ECU fault; consult service manual for PCM bench tests.
- After repair, clear codes, perform relearn procedures if required, and carry out a test drive to confirm the fault does not return.
Likely causes
- Carbon or soot buildup around valve causing it to stick open
- Actuator electrical failure (no torque or step response)
- Damaged valve linkage or missing return spring
- Intermittent open/short in harness under hood or at valve connector
- Contaminated or collapsed vacuum hose (if vacuum operated)
- Failed position sensor that reports valve open when it is closed
Fault status
Status
ETS valve stuck open — control unit detects valve remains in or reports open position and cannot move it to commanded closed position. MIL illuminated and fault stored.
Repair difficulty: Medium
Diagnostic time: 0.5–2.0 hours
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