Fuel SystemModerate✅ DIY Friendly

P0173

Q: What does OBD2 code P0173 mean?

P0173 means: Fuel Trim Malfunction Bank 2. Fuel trim on Bank 2 is out of range.

Fuel Trim Malfunction Bank 2

Fuel trim on Bank 2 is out of range.

SeverityModerate

CategoryFuel System

Est. Repair Cost$50–$400

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›Vacuum leak Bank 2 side
›MAF sensor issue
›O2 sensor fault Bank 2
›Fuel delivery issue

⚠️ Symptoms

›Rough idle
›Check engine light
›Hesitation

✅ How to Fix — Step by Step

Step 1:Smoke test Bank 2 intake
Step 2:Check MAF sensor
Step 3:Test Bank 2 O2 sensor
Step 4:Check fuel pressure

🔧 Diagnostic Tools Required

✔OBD-II Diagnostic Scanner
✔Digital Multimeter
✔Basic Hand Tools
✔Flashlight
✔Vehicle Service Manual

Using the correct diagnostic tools helps identify the root cause of P0173 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: Compare Bank 1 and Bank 2 fuel trims to isolate whether the issue is global or bank-specific.

Frequently Asked Questions

What does OBD2 code P0173 mean?+

P0173 stands for Fuel Trim Malfunction Bank 2. Fuel trim on Bank 2 is out of range.

What causes code P0173?+

Vacuum leak Bank 2 side; MAF sensor issue; O2 sensor fault Bank 2; Fuel delivery issue

How do I fix code P0173?+

Smoke test Bank 2 intake; Check MAF sensor; Test Bank 2 O2 sensor; Check fuel pressure

How much does it cost to fix P0173?+

Estimated repair cost for P0173 is $50–$400.

Is P0173 DIY-friendly?+

Yes — P0173 is generally DIY-friendly with basic tools.

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