P0171 on a Ram 1500
P0171 means system Too Lean (Bank 1). On the 1500, a few causes come up far more than others.
What P0171 usually means on a 1500
P0171 means the Ram's PCM is adding fuel because bank 1 keeps reading lean. On the 5.7 HEMI a broken exhaust manifold bolt is a real possibility here too: the resulting leak can let air reach the front oxygen sensor and fool it into commanding more fuel, mimicking a true lean condition. The more ordinary causes, an intake or vacuum leak, a PCV problem, or weak fuel delivery, also apply. Because a manifold leak explains both a cold tick and a lean code, it is worth checking early on a HEMI.
Most common causes on the 1500
- Exhaust manifold leak skewing the front sensor
On the HEMI a broken-bolt leak near the sensor can pull the readings lean and set P0171 without a genuine mixture problem.
- Vacuum or intake leak
Cracked hoses or a leaking gasket let in unmetered air and lean out the bank.
- PCV system leak
A failing PCV path adds unmetered air and leans the mixture.
- Weak fuel delivery
A tired pump or dirty injectors produce the same lean trims and warrant a pressure check.
What P0171 costs to fix on a 1500
A smoke test and a manifold inspection are the efficient first steps and are inexpensive. If the cause is an intake or PCV leak, the repair is usually in the low hundreds; a manifold-bolt repair costs more in labor because of extraction, and a fuel pump more still. Ruling out the air-side and exhaust-leak causes first avoids replacing fuel parts on a guess.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Ram 1500
Related symptoms
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0171 behavior is covered on the main P0171 page. Confirm with a scan tool before buying parts.
P0171 on your 1500?
Every problem becomes a Case. Tell Redline what your 1500 is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.