Air Throttle & Intake Throttle Control Fault Codes
On many Tier-3/Tier-4 John Deere engines, the air throttle (intake throttle) is used to manage airflow during EGR operation, smooth shutdowns, and assist certain regeneration or derate strategies. While it’s not a driver-controlled throttle like a gasoline engine, its position and response are critical to stable idle quality, emissions, and transient response. When wiring, calibration, or the motor itself fails, the ECU raises specific John Deere codes that point you toward a quick fix—if you know how to read them.
This guide covers the factory codes you provided for the air throttle and closely related actuator control families: ECU 000051.xx (air throttle signal and fault), the later actuator/learn families ECU 003464.xx and ECU 003465.xx, and the generic actuator signal checks ECU 003473.xx.
ECU 000051.03 — Air Throttle Actuator Position Signal Out of Range High
Meaning: The position feedback returns a voltage too high (often a short to 12 V).
Symptoms: Rough idle, stumbling on decel, EGR control errors, intake “whoosh” sounds as the blade oscillates, immediate MIL.
Likely causes: Signal wire rubbed into B+, water bridging pins at the connector, sensor element failure inside the throttle body.
Fix (quick path):
- KOEO (key on, engine off) read position % on the scan tool. If pegged high, unplug the throttle: does the reading fall to default?
- If yes, replace the throttle (sensor internal failure).
- If no, repair harness short to 12 V; clean and re-pin corroded terminals.
ECU 000051.04 — Air Throttle Actuator Position Signal Out of Range Low
Meaning: Feedback is too low (short to ground).
Symptoms: Sluggish response when EGR commands airflow changes, unstable idle, repeat derate.
Causes: Grounded signal leg, water in connector, failed sensor track.
Fix: Inspect loom near brackets; repair grounded conductor; if wiring is sound, replace the throttle assembly.
ECU 000051.07 — Air Throttle Actuator Fault
Meaning: Desired vs actual blade angle don’t match—it’s sticking, slow, or not moving.
Symptoms: Hesitation on tip-in, stalling when returning to idle, EGR-related smoke, code returns after clearing.
Causes: Carbon/oil contamination on the blade, weak motor, jammed gears, binding shaft.
Fix: Remove ducting, inspect blade for gum; clean with sensor-safe solvent while protecting the motor. If mechanical binding persists, replace the body. Perform the learn/calibration routine afterward.
ECU 000051.14 — Air Throttle & EGR Valve Connectors Swapped
Meaning: ECU detects the air throttle connector and EGR valve connector are exchanged—surprisingly common after service.
Symptoms: Both actuators behave erratically; EGR learns fail; multiple position DTCs.
Fix: Trace harness, confirm keyed connectors, swap to correct components, clear codes, run both learn procedures.
ECU 003464.05 / .06 — Air Throttle Actuator, Resistance Too High / Too Low
Meaning: Coil/circuit open (05) or shorted to ground (06).
Symptoms: Immediate MIL, no movement on command, fuse may blow (06).
Fix: Ohm the actuator pins against spec; inspect for pin drag; repair open/short; replace actuator if resistance is out of spec.
ECU 003464.07 — Air Throttle Actuator Fault
Meaning: Commanded angle not achieved (dynamic error).
Fix: Verify clean, free-moving blade; check supply voltage drop under actuation (<0.5 V); recalibrate.
ECU 003464.13 — Air Throttle Actuator Calibration Error
Meaning: The learn routine can’t complete—end stops not found or feedback unstable.
Fix: Ensure ducting isn’t physically limiting travel; check for play in the gearset; replace unit if learn fails twice with good power/ground.
ECU 003465.05 / .06 / .07 / .13 — Air Throttle (Redundant Path)
These mirror the 3464 family but may refer to a second channel or variant actuator. Treat identically: open/short (05/06), mismatch (07), or not calibrated (13). Always fix power/ground and mechanical binding before blaming the controller.
ECU 003473.03 / .04 / .07 — Actuator Signal Out of Range High / Low / Fault
Meaning: A higher-level actuator plausibility check failed—often accompanies the throttle-specific codes.
Fix: Use these as confirmation; solve the 51.xx or 3464/3465 root cause and these typically clear.
Step-by-step workflow that saves time
- Power & ground first: With actuator commanded, check supply sag and ground drop (<0.2–0.3 V).
- Unstick the mechanics: Clean blade and bore; verify smooth motion by hand (with power disconnected).
- Verify feedback: KOEO sweep test—does position change smoothly without jumps?
- Run the learn: Many codes persist until you perform the post-repair calibration.
- Harness protection: Sleeve and secure the pigtail—vibration chafe is the #1 repeat offender.
Prevention: Keep the intake tract clean (filter health, no oil-soaked hoses), avoid pressure-washing connectors, and run periodic learn routines after replacing intake or EGR components.
