Honda-specific code — factory diagnostic data| DTC Data Sheet | |
| Code | P0171 |
| Vehicle | Honda Accord (2003-2024) |
| Engine | 2.4L K24 / 3.5L J35 V6 / 1.5L L15 Turbo |
| System | FUEL AND AIR METERING |
| Fault type | Performance |
| Official meaning | System Too Lean (Bank 1) |
Definition source: Honda factory description. Diagnostic guidance is based on factory-defined fault logic for this code.
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Looking for the cross-vehicle definition? Read the generic P0171 article for the SAE-defined fault logic that applies to all manufacturers.
P0171 Quick Answer
P0171 on a Honda Accord has the same pattern as the Civic but with the V6’s J35 adding intake manifold-specific issues. Top causes: PCV valve failure (Honda-typical), MAF contamination, intake manifold gasket leak (especially the J35 V6 IMRC actuator gasket), and brake booster hose cracks. PCV is the first check on any Honda P0171.
What Does P0171 Mean on a Honda Accord?
The Honda Accord (2003-2024) stores P0171 when the condition described above is met. This guide covers all Accord engine variants from the 2.4L K24 4-cylinder to the 3.5L J35 V6 and 1.5L L15 turbo. Model-specific failure patterns documented below differ from the generic SAE definition.
Symptoms
- Check Engine Light (P0171)
- Rough idle, smooths above 1500 RPM
- Hesitation on tip-in
- Slight fuel economy loss
- Possible P0300 as condition worsens
Common Causes (Most Likely on This Model First)
- Failed PCV valve. Honda-typical high-frequency cause. Stuck-open creates a vacuum leak beyond fuel-trim compensation.
- MAF sensor contamination. Oil mist from blow-by coats the MAF wire. Clean with CRC MAF cleaner.
- Intake manifold gasket leak. The J35 V6 IMRC (Intake Manifold Runner Control) actuator gasket is a known leak point on 2008-2012 Accords.
- Brake booster hose crack. The molded hose develops cracks where it bends after 80k+ miles.
- Failing fuel injector. Less common; partially-clogged injector causes cylinder-specific lean.
- Worn upstream O2 sensor. Honda O2 sensors are good for 100-120k miles.
Diagnostic Approach
- Read freeze frame, LTFT B1 > +15% significant.
- Inspect PCV valve first — easy and common fix on Hondas.
- Clean MAF with CRC MAF cleaner.
- Smoke-test intake. On J35 V6: inspect IMRC actuator gasket for leaks.
- Inspect brake booster hose for cracks.
- Check upstream O2 sensor response on a scan tool if over 100k miles.
Possible Fixes
| Fix | When |
|---|---|
| PCV valve replacement | Always first on Hondas |
| MAF cleaning / replacement | MAF contaminated |
| IMRC actuator gasket (J35 V6) | 2008-2012 V6, smoke at IMRC |
| Brake booster hose | Cracks visible |
| Upstream O2 sensor | O2 > 100k miles, slow response |
Can I Still Drive With P0171?
Yes short-term. Extended lean operation damages the cat — fix within a few weeks.
How Serious Is This Code?
Moderate. Lean condition compounds.
Repair Costs
| Repair | Cost |
|---|---|
| PCV valve | $40 – $120 |
| MAF cleaning | $10 |
| MAF sensor | $140 – $280 |
| IMRC actuator gasket (V6) | $340 – $580 |
| Upstream O2 sensor | $160 – $280 |
FAQ
What is the most common cause of P0171 on a Honda Accord?
The PCV valve — same as the Civic. Hondas tend to have PCV valves fail at higher rates than other brands. Always check PCV first. Then MAF contamination. On J35 V6 Accords (2008-2012), the IMRC actuator gasket is a third common cause.
How much to fix P0171 on a Honda Accord?
PCV valve: $40-$120. MAF cleaning: $10. MAF replacement: $140-$280. IMRC gasket on V6: $340-$580. Most Accord P0171s resolve in the $10-$200 range.
Can a vacuum leak cause P0171 on the Accord V6?
Yes — the J35 V6’s IMRC (Intake Manifold Runner Control) actuator gasket is a known leak point on 2008-2012 Accords. Smoke-test the intake to confirm. The gasket replacement runs $340-$580.
Will P0171 hurt my Accord engine?
Extended lean operation eventually damages the catalyst — P0420 typically appears after months of unaddressed P0171. Fix the lean condition early to avoid the cat replacement cascade.