SPN 27 FMI 0 — EGR Valve Position Above Normal
EGR position above normal is feedback-range diagnosis first. Valve assemblies replaced for position sensor range faults without circuit proof is the most documented misdiagnosis on this fault class.
Fault Overview
SPN 27 FMI 0 indicates the EGR position sensor is reporting above the maximum calibrated range. Position sensor bias high, open ground, mechanical over-travel rare, and connector faults are the primary causes. Ground and signal integrity at the position sensor must be verified before any valve assembly replacement.
Engine & Platform Coverage
Symptoms
- •EGR position reading above maximum range on scan tool
- •Position sensor electrically high at commanded closed
- •Valve assembly replaced without resolving the range fault
- •Ground fault at the position sensor connector
Possible Causes
- 1.Position sensor bias high producing false above-range reading
- 2.Open ground at the position sensor connector
- 3.Connector fault at the position sensor
- 4.Mechanical over-travel — rare
Diagnostic Flow — FSM Sequence
AI Diesel Tech enforces this evidence-gate sequence. Each gate must pass before advancing.
2 steps locked behind Technician Mode- 1Step 1 — Closed-Position Correlation: At commanded closed, the position should read near the OEM closed value. An electrically high reading at commanded closed supports a sensor or circuit fault rather than actual over-travel.
- 2Step 2 — Circuit Checks: Verify ground and signal integrity at the position sensor connector. An open ground can drive the signal high. A connector fault can produce an intermittent or sustained high reading.
- 3Step 3 — Sensor or Assembly Replacement After Proof: Replace the position sensor or valve assembly only after the circuit is proven intact and the sensor itself is confirmed to be biased high.
Unlock the full evidence-gated diagnostic sequence, DVOM test steps, and repair procedures in Technician Mode.
Repair Steps
1 steps locked- 1Repair open ground at the position sensor connector.
- 2Repair connector fault at the position sensor.
- 3Replace position sensor or valve assembly after circuit proof confirms sensor bias high.
Unlock full diagnostic steps, DVOM tests, and repair procedures.
Full Diagnostic Access
Verification steps, preventative measures, severity guidance, and legacy comparison are available in Technician Mode.
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Related Resources
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Summary
SPN 27 FMI 0 is an EGR position range fault. Prove ground and signal circuit integrity before any valve assembly replacement.