The 2022 Ram ProMaster's check engine light with hesitation often indicates a lean running condition (code P0171), where the engine receives too much air relative to fuel. This affects commercial operation and fuel economy.
ProMaster Engine Options
The ProMaster offers 3.6L Pentastar V6 and 2.4L four-cylinder options. Both can experience lean conditions from similar causes, though diagnosis specifics vary.
Causes of Lean Running
Vacuum Leaks
Intake manifold gaskets, vacuum hoses, and PCV system components can leak, allowing unmetered air into the engine. The large intake manifolds in commercial vans create multiple potential leak points.
MAF Sensor Issues
A contaminated or failing mass airflow sensor underreports air entering the engine, causing lean fuel calculations.
Fuel Delivery Problems
Low fuel pressure from a weak pump, clogged filter, or restricted lines reduces fuel delivery. Dirty injectors may not deliver adequate fuel volume.
Exhaust Leaks
Leaks before the upstream oxygen sensor can draw air, fooling the sensor into reporting lean conditions.
Hesitation Correlation
Lean conditions cause hesitation during acceleration when the engine needs more fuel than is being delivered.