What This Sensor Does
The IAT sensor threads into the intake boss and reads the temperature of the air charge entering the engine. The ECM uses that reading alongside boost and engine speed to set injection timing and fueling. Cold, dense air needs different timing than hot air coming off a heat-soaked charge pipe, and the sensor is what tells the module which one it is looking at.
It is a two-wire thermistor. Resistance falls as air temperature climbs, and the ECM reads the voltage drop across the circuit. There are no moving parts, so failure is almost always electrical: a cracked element, a corroded pin, or a chafed harness lead shorting the signal wire to ground or to the reference voltage.
This aftermarket unit uses a premium quality sensing element for stable, repeatable readings and a sealed two-pin connector built to handle heat, oil mist and vibration under the hood. It drops into the factory intake boss with no modification to the manifold or the harness.
Why These Numbers Cross
3408345 is the headline number and the one most shops write on the box. Cummins 3865345 is the same sensor carried under a different number, and Mopar 5014197AA is the number it shipped under when the B-Series engine went into Dodge Ram chassis. PAI lists it as 050675. All four describe one two-pin intake air temperature thermistor with the same thread form and the same electrical characteristics.
Numbers multiply because the same sensor moves through engine, chassis and aftermarket supply channels, and each channel assigns its own part number. Supersessions add more. That is why a truck can have a Mopar number on the old sensor while the engine data plate points at a Cummins number — same hardware, different paperwork trail.
Treat the cross-reference as a starting point, not a guarantee. Read the number stamped on the sensor you are pulling, or verify against your engine serial number, before you commit. These numbers are listed for identification only.
Checks Before You Order
Pull the connector and look at the pins first. Green corrosion, a spread terminal or a pushed-back pin will throw the same codes as a dead sensor and swapping the part fixes nothing. Wiggle-test the harness back toward the loom with the key on and watch the live data for a temperature reading that jumps.
Compare the IAT reading to coolant temperature after the truck has sat overnight. Both should land within a few degrees of ambient. A sensor reading wildly off on a cold soak is bad. One that reads fine cold but drifts once the engine is hot is usually a cracked element or a marginal connector, and it still needs replacing.
3408345 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3408345. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| Cummins | 3865345 |
| Mopar | 5014197AA |
| PAI | 050675 |
Frequently asked questions
Will 3865345 or 5014197AA work in place of 3408345?
Those numbers are listed because they identify the same two-pin intake air temperature sensor through different supply channels. This part is a direct replacement for 3408345 and cross-references to Cummins 3865345, Mopar 5014197AA and PAI 050675. Confirm by reading the number on the sensor you are removing or by checking your engine serial number before ordering.
What does a failed intake air temperature sensor do to the engine?
The ECM loses accurate charge air temperature and falls back on a default value, so injection timing and fueling stop matching real conditions. You typically see hard cold starts, rough running until the engine warms, and reduced fuel economy. A fault code for the intake air temperature circuit usually sets, though a drifting sensor can degrade driveability without ever tripping a code.
Does this sensor fit the factory intake boss without modification?
It is built to fit the factory intake boss on Cummins ISB 5.9L and QSB 5.9L B-Series 24V engines with no modification to the manifold or harness. Fitment still needs to be confirmed against your engine serial number or the number stamped on the old sensor, since the same engine family was built in several configurations.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
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Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.