Code
P1485
LINCOLN
P — Powertrain
EGRV Circuit Malfunction
Views:
UK: 30
EN: 53
RU: 42
AI status
Completed
Completed
100%
Causes
- Open or short in EGR valve wiring harness
- Corroded or loose EGR valve connector
- Failed EGR valve actuator (solenoid, stepper or vacuum transducer)
- Failed EGR valve position/sensor (if equipped)
- Clogged EGR passages or valve stuck
- Poor ground or blown fuse/relay feeding the EGR circuit
Symptoms
- Check Engine/Service Engine Soon lamp illuminated
- Rough idle or hesitation
- Reduced engine performance or drivability complaints
- Possible increased NOx emissions or failed emissions test
- Codes related to EGR flow or EGR position may also be present
What to check
- Read all stored/active codes and freeze-frame data; note pending or manufacturer-specific codes
- Visually inspect EGR valve, connector and wiring for damage, corrosion, pin push-out or rodent chew
- Check EGR circuit fuse and related relays (if applicable)
- Backprobe EGR connector with key ON (engine OFF) to verify supply voltage and ground
- With a scan tool command the EGR actuator and observe response (actuator movement or position feedback)
- Measure resistance of EGR solenoid/actuator coil (compare to specification) and check continuity to PCM
Signal parameters
- Power feed (key ON): battery voltage (~10–14 V) at EGR module/valve power pin (varies by system)
- Ground continuity: near 0 Ω between EGR ground and battery negative
- Actuator coil resistance (typical): 20–60 Ω (varies by design) — consult vehicle specs
- Position sensor output (if equipped): variable voltage ~0.5–4.5 V depending on valve position
- Command signal: PWM duty cycle or switched 0–12 V; expected range 0–100% duty cycle when commanded
- PWM frequency: system dependent (typical tens to a few hundred Hz) — refer to vehicle service data
Diagnostic algorithm
- Verify the concern and note any additional DTCs. Capture freeze-frame and live data for EGR position, commanded duty and related sensors.
- Perform a visual inspection of the EGR valve, vacuum hoses (if vacuum-operated), connector and wiring for damage or corrosion.
- Check fuses/relays and battery/charging system to ensure proper supply voltage.
- Backprobe the EGR connector: with key ON verify power and ground. Start the engine (if safe) and observe changes. Record voltages.
- Use a scan tool to command the EGR valve while monitoring actual position/feedback. If commanded change is not seen, proceed to electrical tests.
- Test continuity and resistance of control and feedback circuits between the EGR connector and PCM. Check for shorts to battery positive or ground.
- Bench-test the EGR actuator: apply appropriate voltage or vacuum and verify mechanical movement and position feedback (do this per manufacturer safety procedures).
- If EGR is sticking, remove and inspect/clean carbon deposits in the valve and intake passages. Replace if mechanically damaged or nonfunctional.
- If wiring, connector and EGR valve test good but fault persists, consider PCM connector inspection and possible PCM fault — confirm with known-good module or manufacturer guidance before replacement.
- After repairs, clear codes and perform a road/drive cycle or required readiness procedure to confirm the repair. Re-scan for returned codes.
Likely causes
- Damaged or corroded connector at the EGR valve
- Open/short in the EGR control or sensor wires between EGR valve and PCM
- Failed EGR valve actuator (no response to command)
- Stuck or carbon-clogged EGR valve preventing expected position feedback
- Intermittent ground or supply to the EGR circuit
Fault status
Status
PCM detected an abnormal condition in the EGR valve control circuit (P1485). The circuit may have an open/short, poor connection, or the EGR actuator/sensor may be malfunctioning. Further diagnosis required.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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