A failed downstream oxygen sensor that is stuck at a high voltage or contaminated; A rich fuel mixture caused by leaking fuel injectors or high fuel pressure; A faulty engine coolant temperature sensor that keeps the engine in open-loop enrichment; A dirty or failing mass airflow sensor reporting more air than actually enters the engine; A restricted air intake or clogged air filter reducing actual airflow; A leaking or stuck-open purge solenoid allowing fuel vapor into the intake; Wiring damage or corrosion in the oxygen sensor circuit causing a false high-voltage reading

DTC codes / Chrysler codes / P1144

P1144 · ChryslerHO2S Bank 1 Sensor 3 Rich Or High Voltage

Q: What does code P1144 mean?

HO2S Bank 1 Sensor 3 Rich Or High Voltage. P1144 on Chrysler vehicles means the powertrain control module has detected a rich condition or abnormally high voltage signal from the downstream oxygen sensor on bank 1, which is sensor 3 after the catalytic converter. The computer compares this signal against expected values and flags the code when the sensor reports a persistently rich exhaust mixture or a voltage that stays above the normal switching range.

P1144 on Chrysler vehicles means the powertrain control module has detected a rich condition or abnormally high voltage signal from the downstream oxygen sensor on bank 1, which is sensor 3 after the catalytic converter. The computer compares this signal against expected values and flags the code when the sensor reports a persistently rich exhaust mixture or a voltage that stays above the normal switching range.

SystemPowertrain

Code typeChrysler specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
A slight decrease in fuel economy as the engine runs richer than commanded
Occasional rough idle or hesitation during acceleration if the rich condition is severe
A sulfur or rotten egg smell from the exhaust in some cases
Failed emissions testing due to elevated hydrocarbon or carbon monoxide levels

Common causes, most likely first

A failed downstream oxygen sensor that is stuck at a high voltage or contaminated
A rich fuel mixture caused by leaking fuel injectors or high fuel pressure
A faulty engine coolant temperature sensor that keeps the engine in open-loop enrichment
A dirty or failing mass airflow sensor reporting more air than actually enters the engine
A restricted air intake or clogged air filter reducing actual airflow
A leaking or stuck-open purge solenoid allowing fuel vapor into the intake
Wiring damage or corrosion in the oxygen sensor circuit causing a false high-voltage reading

How to diagnose and fix it

Scan all stored and pending codes to confirm P1144 is the primary fault and not a side effect of another code
Inspect the downstream oxygen sensor wiring and connector for chafing, corrosion, or loose pins
Use a scan tool to view live data for the bank 1 sensor 3 voltage and compare it to the upstream sensor
Check fuel trims and coolant temperature readings to determine whether the rich condition is real or sensor-induced
Test fuel pressure and inspect injectors for leaks if the rich condition is confirmed
Replace the downstream oxygen sensor if its signal is stuck high or responds sluggishly
Clear the codes and perform a drive cycle to verify the repair and confirm the code does not return

Downstream sensor voltage traps to avoid

A downstream oxygen sensor that reads a steady high voltage can be a normal response to a genuinely rich mixture, so replacing the sensor without checking fuel trims often leads to a repeat failure.
Chrysler downstream sensors on some models are sensitive to exhaust leaks before the sensor, which can draw in air and skew the reading in ways that mimic a rich condition.
A stuck-open thermostat or a coolant temperature sensor that reads cold can keep the PCM in enrichment mode, driving the downstream sensor high without any sensor fault at all.
Aftermarket oxygen sensors with incorrect resistance values are a common cause of repeat P1144 codes on Chrysler vehicles, so matching the OEM specification matters.
The code can set intermittently from a poor ground connection at the sensor body, which is easy to overlook when the sensor itself tests good on the bench.

Can I keep driving with P1144?

You can usually continue driving with P1144, but avoid heavy acceleration and long trips until the cause is found because a persistent rich condition can damage the catalytic converter and increase emissions. If the check engine light begins flashing or the engine runs rough, stop driving and have the vehicle inspected promptly.

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.