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DTC codes / Chrysler codes / P1298

P1298 · ChryslerLean Operation At Wide Open Throttle

P1298 on Chrysler vehicles means the powertrain control module (PCM) has detected a lean air/fuel mixture during wide open throttle (WOT) operation, where the engine is under maximum load and the throttle is fully open. The PCM monitors fuel trim and oxygen sensor feedback and sets this code when the mixture stays leaner than commanded for a calibrated time, indicating the engine is not receiving enough fuel or is taking in unmetered air.

SystemPowertrain
Code typeChrysler specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Engine hesitation or stumble during hard acceleration or when merging onto the highway
  • Reduced power at wide open throttle, sometimes felt as a flat spot or lack of pull
  • Occasional engine ping or spark knock under heavy load due to lean conditions
  • Poor fuel economy or rough idle in some cases, though less common with this specific code

Common causes, most likely first

  1. Vacuum leak from a cracked or disconnected intake hose, intake manifold gasket, or PCV hose
  2. Weak or failing fuel pump that cannot maintain pressure and volume under high demand
  3. Clogged fuel filter restricting fuel flow during wide open throttle
  4. Dirty or failing mass airflow (MAF) sensor under-reporting incoming air
  5. Leaking intake manifold gasket allowing unmetered air into the engine
  6. Faulty oxygen sensor or wiring giving inaccurate feedback to the PCM
  7. Exhaust leak upstream of the oxygen sensor causing false lean readings

How to diagnose and fix it

  1. Inspect all intake and vacuum hoses for cracks, loose clamps, or disconnected lines, and repair as needed
  2. Check fuel pressure and volume with a gauge under load; compare to Chrysler specifications and replace the fuel filter if restricted
  3. Clean the mass airflow sensor with approved cleaner and verify its readings with a scan tool
  4. Perform a smoke test on the intake system to locate hidden vacuum leaks
  5. Test the oxygen sensor response and wiring for shorts or opens, replacing if faulty
  6. Inspect for exhaust leaks before the upstream oxygen sensor and repair any leaks
  7. If all else checks out, verify fuel pump operation under load and replace if it cannot sustain pressure

Before you replace the fuel pump

  • A dirty mass airflow sensor often causes this code on Chrysler engines because it under-reports airflow, leading to a lean condition at wide open throttle that mimics a fuel delivery problem.
  • Intake manifold gasket leaks on Chrysler V6 and V8 engines can be intermittent and only show up under high vacuum, so a visual inspection may miss them without a smoke test.
  • The code can be set by a weak fuel pump that still provides adequate pressure at idle but cannot keep up with volume demand at wide open throttle, so a simple pressure check at idle is not enough.
  • Exhaust leaks upstream of the oxygen sensor can draw in outside air and cause the sensor to report a false lean condition, leading to unnecessary fuel system repairs.
  • Some Chrysler vehicles are known for wiring harness chafing near the oxygen sensor or MAF sensor, causing intermittent lean readings that set P1298 without any mechanical fault.

Can I keep driving with P1298?

You can drive the vehicle gently to a repair shop, but avoid wide open throttle and heavy acceleration until the fault is fixed. Prolonged lean operation under load can cause overheating and damage to pistons or valves, so have it diagnosed promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Chrysler vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage