Engine misfire causing unburned fuel to enter the exhaust and burn in the converter; Rich fuel mixture from a faulty fuel injector, fuel pressure regulator, or coolant temperature sensor; Faulty downstream oxygen sensor sending an erroneous signal that the PCM interprets as overheat; Exhaust restriction such as a collapsed substrate or damaged pipe raising converter temperature; Ignition timing retarded beyond specification due to knock sensor or cam/crank correlation issues; Aging or contaminated catalytic converter that no longer manages heat properly; Wiring or connector damage to the downstream oxygen sensor or exhaust temperature sensor circuit

DTC codes / Chrysler codes / P1484

P1484 · ChryslerCatalytic Converter Overheat Detected

Q: What does code P1484 mean?

Catalytic Converter Overheat Detected. P1484 on Chrysler vehicles means the powertrain control module has calculated that the catalytic converter temperature has exceeded a safe threshold, typically based on upstream and downstream oxygen sensor readings and exhaust temperature modeling. The computer is not measuring converter temperature directly; it infers overheating from sensor behavior and may also illuminate the check engine light or a message in the driver information center.

P1484 on Chrysler vehicles means the powertrain control module has calculated that the catalytic converter temperature has exceeded a safe threshold, typically based on upstream and downstream oxygen sensor readings and exhaust temperature modeling. The computer is not measuring converter temperature directly; it infers overheating from sensor behavior and may also illuminate the check engine light or a message in the driver information center.

SystemPowertrain

Code typeChrysler specific

SeverityMedium

Fix difficultyProfessional

AreaAuxiliary emission controls

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms
A message in the driver information center warning of catalytic converter overheat or exhaust system service
Reduced engine power or limp mode in some Chrysler models when the overheat condition is severe
Rotten egg sulfur smell from the exhaust after driving
Heat discoloration or glowing visible under the vehicle in extreme cases
Poor fuel economy or rough running if the root cause is misfire or rich mixture

Common causes, most likely first

Engine misfire causing unburned fuel to enter the exhaust and burn in the converter
Rich fuel mixture from a faulty fuel injector, fuel pressure regulator, or coolant temperature sensor
Faulty downstream oxygen sensor sending an erroneous signal that the PCM interprets as overheat
Exhaust restriction such as a collapsed substrate or damaged pipe raising converter temperature
Ignition timing retarded beyond specification due to knock sensor or cam/crank correlation issues
Aging or contaminated catalytic converter that no longer manages heat properly
Wiring or connector damage to the downstream oxygen sensor or exhaust temperature sensor circuit

How to diagnose and fix it

Scan all modules for stored and pending codes, and record freeze-frame data to see the conditions when P1484 set
Inspect the downstream oxygen sensor and its wiring for damage, corrosion, or loose connections
Check for engine misfire codes and perform a cylinder balance or misfire counter test
Measure fuel trims and fuel pressure to identify a rich condition before condemning the converter
Verify exhaust backpressure with a gauge or vacuum test to rule out a restricted exhaust
Compare upstream and downstream oxygen sensor waveforms on a scan tool to confirm converter efficiency and heat behavior
Replace the catalytic converter only after all root causes of overheating have been corrected and verified

Before you replace the catalytic converter

A P1484 is often a symptom of an underlying misfire or rich condition, so replacing the converter without fixing the root cause will quickly destroy the new unit.
Chrysler models may set P1484 from a lazy downstream oxygen sensor that reports a lean condition the PCM interprets as converter overheat, even when the converter is physically fine.
Exhaust leaks upstream of the downstream oxygen sensor can pull in outside air and skew readings, causing a false overheat calculation.
Some Chrysler vehicles use a calculated converter temperature model rather than a dedicated sensor, so wiring faults in the oxygen sensor circuit can mimic a converter problem.
A restricted exhaust from a collapsed converter substrate can cause both overheating and power loss, and the restriction may not set a separate code.

Can I keep driving with P1484?

You can drive a short distance to a repair shop if the engine runs normally and the light is steady, but avoid heavy throttle, towing, and long trips until diagnosed. If the check engine light flashes or you notice a sulfur smell or power loss, stop driving to prevent converter damage and fire risk.

Tools that help

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