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P0172HondaHonda Civic HubAll Honda P0172Medium Severity

P0172 on Honda Civic: Fix & DLC Location

Factory diagnostic troubleshooting wire for fault code P0172 (System Too Rich (Bank 1) - Symptoms, Causes & Step-by-Step Fix) specifically on the Honda Civic (2020–2026, 2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid).

Honda Civic
DIY Parts Estimate
$30 - $280 (DIY Clean: $15)
Civic OEM Fitment
Shop Labor Quote
$180 – $380
Based on $115/hr labor
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. DIY Time
45 – 90 Min
Basic hand tools
Check P0172 On Another Honda Model:
Honda CivicHonda AccordHonda CR-VHonda Pilot

1. Symptoms of P0172 on Honda Civic

When the Engine Control Module (ECM/PCM) on your Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid) logs fault code P0172, drivers commonly observe:

Check Engine Light on on Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid)
Strong unburnt fuel odor from exhaust on Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid)
Black carbon soot around exhaust tip on Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid)
Rough idle and engine bogging under throttle on Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid)
Noticeable drop in MPG on Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid)
Honda Civic OBD-II Port Location
The 16-pin diagnostic connector is located Under driver dash, right side of steering column. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Honda Civic

Historical warranty claims and technical repair bulletins for Honda Civic point to the following failure distribution:

55%
Faulty or leaking fuel injector (Honda OEM Part)
25%
Contaminated Mass Air Flow (MAF) sensor (Honda OEM Part)
12%
Stuck closed EVAP canister purge valve (Honda OEM Part)
8%
Excessive fuel pressure regulator failure (Honda OEM Part)

3. Step-by-Step DIY Repair Guide for Honda Civic

01
Clean MAF Sensor and Throttle Body

Use dedicated MAF cleaner to remove carbon buildup from sensor wires. on the Honda Civic equipped with 2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid.

02
Check Short Term & Long Term Fuel Trims

Use live OBD-II scanner data; negative trims beyond -10% indicate the ECU is cutting fuel. on the Honda Civic equipped with 2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid.

03
Inspect Fuel Injector Leak-Down

Perform a fuel pressure leak-down test to identify injectors leaking raw gasoline into cylinders while parked. on the Honda Civic equipped with 2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid.

Other Common Fault Codes on Honda Civic

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Honda Civic:

4. Honda Civic P0172 FAQs

What causes code P0172 to trigger on a Honda Civic?

On the Honda Civic (2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid), P0172 is most frequently caused by Faulty or leaking fuel injector or Contaminated Mass Air Flow (MAF) sensor.

Where is the OBD-II port located on my Honda Civic?

On the Honda Civic, the 16-pin DLC diagnostic connector is located Under driver dash, right side of steering column. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Honda Civic with code P0172?

Driveable short distances, but unburnt fuel can damage catalytic converters. Given that P0172 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.