

2006 Mercedes ML350 (W164) — Cranks but won't start, multiple systems checked out fine
Car suddenly wouldn't start — worked fine that morning, dead by that afternoon. No slow decline beforehand.
Symptoms:
Cranks strong and consistently — no slow/labored cranking
Dash lights come up fully, no dimming during crank
Fuel pump primes normally (hear the whir when key goes to position 2)
Serpentine belt spins normally during crank (confirmed engine is actually turning over)
Steering wheel unlocks fine when cranking (no longer locked)
OBD2 scan (standard, not Mercedes-specific) shows no codes at all
Dash intermittently shows a "remove key" message — not every attempt, inconsistent
SRS "Restraint system malfunction, drive to workshop" warning also present (unsure if related)
A high-pitched whir noise heard during cranking, traced to alternator area (confirmed separate from starter — belt/pulleys were visibly spinning normally)
Charged all batteries fully — no change
OBD2 scan — no codes
Mobile mechanic came out, said "no issue found" but tried to sell a new programmed key without actually diagnosing further
Locksmiths say "if it cranks and wheel unlocks, it can't be the immobilizer" — not sure this is accurate for this platform
My leading theories (unconfirmed):
ELV/EZS steering lock module failing to complete electronic handshake with ECU (even though mechanical unlock works)
Crank/cam position sensor signal issue (wouldn't always throw a code)
Fuel pressure problem despite pump priming normally
Possible wiring/ground fault
Question: Has anyone dealt with this exact pattern on a W164? Is this consistent with ELV/EZS, or does the "remove key" message + good crank + no codes point somewhere else? Trying to figure out what question to ask a shop before paying for more diagnostics.