A failed or contaminated intake manifold pressure sensor, which is the most common cause on higher-mileage Chrysler engines; A cracked, split, or disconnected vacuum hose between the intake manifold and the sensor, causing a false pressure reading; Corroded, loose, or damaged electrical connector terminals at the sensor or PCM; An open or shorted wire in the sensor reference, signal, or ground circuit; Carbon or oil buildup clogging the sensor port or the passage it samples, restricting pressure changes; A faulty PCM driver circuit, though this is rare compared to sensor and wiring faults; An intake manifold vacuum leak elsewhere that skews the pressure the sensor reports

DTC codes / Chrysler codes / P1408

P1408 · ChryslerIntake Manifold Pressure Sensor Circuit

Q: What does code P1408 mean?

Intake Manifold Pressure Sensor Circuit. P1408 on a Chrysler vehicle means the powertrain control module (PCM) has detected an out-of-range signal from the intake manifold pressure sensor circuit, which is used to measure the absolute pressure inside the intake manifold. The PCM compares this sensor's voltage against expected values for the current engine speed and throttle position, and it sets the code when the signal falls outside the acceptable range for a calibrated period.

P1408 on a Chrysler vehicle means the powertrain control module (PCM) has detected an out-of-range signal from the intake manifold pressure sensor circuit, which is used to measure the absolute pressure inside the intake manifold. The PCM compares this sensor's voltage against expected values for the current engine speed and throttle position, and it sets the code when the signal falls outside the acceptable range for a calibrated period.

SystemPowertrain

Code typeChrysler specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough or unstable idle quality, especially when the engine is cold
Hesitation or stumble during light acceleration from a stop
Poor fuel economy or rich-running exhaust smell
Occasional stalling when coming to a stop or during deceleration
A slight loss of power under load, though severe drivability issues are uncommon

Common causes, most likely first

A failed or contaminated intake manifold pressure sensor, which is the most common cause on higher-mileage Chrysler engines
A cracked, split, or disconnected vacuum hose between the intake manifold and the sensor, causing a false pressure reading
Corroded, loose, or damaged electrical connector terminals at the sensor or PCM
An open or shorted wire in the sensor reference, signal, or ground circuit
Carbon or oil buildup clogging the sensor port or the passage it samples, restricting pressure changes
A faulty PCM driver circuit, though this is rare compared to sensor and wiring faults
An intake manifold vacuum leak elsewhere that skews the pressure the sensor reports

How to diagnose and fix it

Inspect the sensor and its vacuum hose for cracks, disconnection, or oil contamination, and replace any damaged hose first
Check the electrical connector at the sensor for corrosion, pushed-out pins, or loose fit, and clean or repair as needed
Use a scan tool to read live intake manifold pressure data and compare it to expected values at idle and with the key on, engine off
Backprobe the sensor signal, reference voltage, and ground wires with a multimeter to confirm the circuit is intact and the sensor output is plausible
Remove and clean the sensor port and passage if carbon or oil sludge is present, then retest before condemning the sensor
Replace the intake manifold pressure sensor if the circuit checks out but the signal remains out of range, then clear the code and verify the repair
If the fault persists after sensor replacement, perform a pinpoint test of the PCM circuits and inspect for intermittent wiring faults before considering PCM replacement

What Chrysler techs check before replacing the sensor

A clogged sensor port from oil vapor or carbon is a frequent cause on Chrysler engines, and cleaning the passage often fixes the code without any new parts.
The intake manifold pressure sensor on many Chrysler engines shares its vacuum source with other components, so a leak at a nearby hose or fitting can set P1408 even when the sensor itself is good.
Intermittent connector faults from engine vibration and heat cycling are common, so wiggle-testing the harness while watching live data can reveal a problem that a static meter check misses.
A dirty throttle body or a vacuum leak elsewhere can cause pressure readings that fall outside the expected range and trigger this code, so a full intake system inspection is worthwhile.
Do not assume the sensor is bad just because the code points to its circuit; the PCM sets this code for any out-of-range signal, including wiring and vacuum supply faults.

Can I keep driving with P1408?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because the incorrect pressure signal can make the engine run rich and may worsen drivability. If the engine idles roughly or stalls, stop driving and have the fault diagnosed 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.