Code
P1520
FORD
P — Powertrain
Intake Manifold Runner Control Circuit Fault
Views:
UK: 34
EN: 80
RU: 34
AI status
Completed
Completed
100%
Causes
- Open or short in IMRC wiring harness
- Corroded, loose or damaged connector at IMRC actuator/solenoid
- Failed IMRC actuator or solenoid (electrical or mechanical failure)
- Stuck or seized intake runner mechanism (carbon buildup or mechanical damage)
- Blown fuse or faulty power/ground supply to the actuator
- PCM/internal driver fault
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine performance or hesitation at certain RPMs
- Rough idle or unstable idle in some conditions
- Poor throttle response and reduced fuel economy
- Occasional surging or lack of power when IMRC is commanded
What to check
- Read PCM for P1520 and any related codes; record freeze‑frame/live data
- Use a scan tool to command IMRC open/close and observe actuator movement and related PID values
- Visually inspect IMRC actuator/solenoid, connector and wiring for damage, corrosion, or pin push‑out
- Backprobe connector with key ON: verify battery voltage at power feed and good ground/PCM drive when commanded
- Measure coil resistance of actuator/solenoid against specification
- Check continuity between IMRC connector and PCM pin to rule out open or short
Signal parameters
- Power feed: approximately battery voltage (~11–14.5 V) at IMRC power terminal with ignition ON
- Control signal: PCM usually switches ground or supplies a pulsed voltage/duty to the actuator (variable by model)
- Typical solenoid/actuator coil resistance: commonly in the range ~10–50 ohms (manufacturer spec required) — open or near zero indicate fault
- Position sensor (if used): 0.5–4.5 V range depending on commanded position (refer to OEM data)
- No movement when commanded or abnormal/erratic voltage indicates electrical or mechanical fault
Diagnostic algorithm
- Retrieve and document all stored codes and freeze‑frame data. Clear codes and attempt to re‑reproduce.
- With a capable scan tool, command the IMRC actuator open/close while observing for physical movement. Note any delays or failure to move.
- Visually inspect the IMRC actuator, connector and wiring harness. Repair any damaged wiring or connectors.
- Backprobe harness: verify battery voltage at the power terminal with ignition ON. Command the PCM to actuate and verify the PCM provides the expected control (ground or pulse) to the actuator.
- Measure actuator coil resistance at the connector; compare to OEM spec. If open/shorted, replace actuator.
- Check continuity between actuator connector and PCM pin to locate open or short circuits; repair wiring as needed.
- Remove and inspect intake runner flaps/linkages for carbon buildup or mechanical binding; clean or repair as required.
- If wiring and actuator are good, suspect PCM driver fault — confirm with scope or swapped known‑good PCM (where applicable) before replacement.
- After repairs, clear codes and road test to confirm proper operation and that the code does not return.
Likely causes
- Damaged insulation and chafed wires causing intermittent short to ground or battery
- Connector corrosion causing high resistance or loss of circuit continuity
- IMRC actuator coil out of specification (open/low resistance or shorted)
- Intake runner flaps or linkages seized by carbon or debris preventing movement
- Missing or removed vacuum line on vacuum‑actuated systems
Fault status
Status
PCM detected a fault in the Intake Manifold Runner Control circuit (open, short, no movement, or abnormal feedback).
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email