A failed intake air high pressure switch that remains open or has high internal resistance.; Damaged, corroded, or disconnected wiring or connector at the switch or PCM.; An open circuit in the signal or ground wire between the switch and the PCM.; High resistance in a splice or terminal within the harness, often due to moisture intrusion.; A faulty PCM driver circuit, though this is less common than wiring or switch failure.; Aftermarket modifications or poor previous repairs that disturb the circuit.

DTC codes / Chrysler codes / P1423

P1423 · ChryslerIntake Air High Pressure Switch Circuit High Voltage

Q: What does code P1423 mean?

Intake Air High Pressure Switch Circuit High Voltage. P1423 on a Chrysler vehicle means the powertrain control module (PCM) has detected an abnormally high voltage on the intake air high pressure switch circuit, which typically indicates an open circuit, a faulty switch, or a wiring problem rather than actual high intake air pressure. The PCM monitors this switch as part of the intake air system to verify pressure readings and adjust fuel and boost control accordingly, and it sets the code when the signal voltage exceeds the expected range for a calibrated time.

P1423 on a Chrysler vehicle means the powertrain control module (PCM) has detected an abnormally high voltage on the intake air high pressure switch circuit, which typically indicates an open circuit, a faulty switch, or a wiring problem rather than actual high intake air pressure. The PCM monitors this switch as part of the intake air system to verify pressure readings and adjust fuel and boost control accordingly, and it sets the code when the signal voltage exceeds the expected range for a calibrated time.

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.
Reduced engine performance or a sudden loss of power under acceleration if the PCM enters a limp mode.
Poor fuel economy or rough running if the fault affects air/fuel ratio calculations.
Intermittent hesitation or stumble during light throttle applications.
In some cases, a stored code but no drivability complaints at all.

Common causes, most likely first

A failed intake air high pressure switch that remains open or has high internal resistance.
Damaged, corroded, or disconnected wiring or connector at the switch or PCM.
An open circuit in the signal or ground wire between the switch and the PCM.
High resistance in a splice or terminal within the harness, often due to moisture intrusion.
A faulty PCM driver circuit, though this is less common than wiring or switch failure.
Aftermarket modifications or poor previous repairs that disturb the circuit.

How to diagnose and fix it

Connect a scan tool and record freeze-frame data to confirm the code and check for related codes in other modules.
Visually inspect the intake air high pressure switch, its connector, and the wiring harness for damage, corrosion, or loose pins.
Disconnect the switch and measure resistance across its terminals; compare to the manufacturer's specification, replacing the switch if out of range.
Backprobe the signal wire at the PCM and check voltage with the key on, engine off; a high voltage near reference voltage indicates an open circuit.
Perform a continuity test on the signal and ground wires between the switch and PCM to locate opens or high resistance.
Repair or replace the faulty section of harness, using proper soldering and heat-shrink techniques, then clear the code and verify the repair with a test drive.
If all wiring and the switch test good, follow the manufacturer's diagnostic flow for PCM internal circuit testing before condemning the PCM.

Don't overlook the intake air pressure switch

A common mistake is replacing the intake air high pressure switch without first checking the connector for pushed-out terminals or corrosion, which can mimic a failed switch.
The code can be set by a simple open circuit caused by a rodent-chewed wire or a chafed harness near the intake manifold, so a thorough visual inspection is essential.
On some Chrysler models, this switch shares a ground with other sensors, and a bad ground can cause multiple codes; always check ground integrity before replacing parts.
A high voltage reading does not always mean the switch is bad; it can also indicate a short to voltage in the signal wire, so test both resistance and voltage.
After repairs, clear the code and perform a readiness drive cycle; the code may not reset immediately if the fault is intermittent, so monitor live data during a test drive.

Can I keep driving with P1423?

You can generally continue driving with this code if the engine runs normally, but avoid heavy acceleration or towing until the fault is repaired because the PCM may not properly control boost or fuel delivery. If the engine enters limp mode or runs poorly, seek service promptly to prevent potential damage.

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.