✅ Fixed
Found: air filter completely clogged, tire pressure 7 PSI low on two tires, upstream O2 sensor reading sluggish. Replaced air filter $22, inflated tires, replaced O2 sensor $75. Fuel economy improved significantly.
BMW 4 Series 2021 Fuel economy dropped poor MPG
BMW
2021
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🔍 Symptoms
⚙️ Causes
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⚡ Quick Summary
Severity Level
Medium
Safe to Drive?
⚠️ Drive with Caution
Safety Impact
Indirect risk — worth monitoring, not urgent
Urgency Level
🟡 Monitor Closely
BMW 4 Series 2021 fuel economy noticeably worse. Filling up more often than usual. No check engine light. 124240 km. This fault code is stored when the engine control unit detects a specific fault condition. Common causes include sensor failures, wiring faults, and component wear. Always read additional fault codes before replacing parts — multiple codes together provide a clearer diagnosis. Clear the code after repair and test drive to confirm the fault does not return.
🔍 Symptoms
📍 Fuel economy dropped — poor MPG
📍 BMW 4 Series
⚙️ Possible Causes
Fuel economy dropped — poor MPG
BMW 4 Series
Possible: Found: air filter completely clogged, tire pressure 7 PSI low on two tires, upstream O2 sensor reading sluggish. Replaced air filter $22, inflated tires, replaced O2 sensor $75. Fuel economy improved significantly.
Repair / Solution
Based on 67 driver confirmations
⚠️ Wrong Diagnosis?
No commonly reported misdiagnoses for this fault yet. If you have replaced a part that did not fix this BMW 2021 problem, submit a wrong diagnosis report — it helps other drivers avoid the same costly mistake.
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