Product Description
The CUMMINS 3923129 OEM CRANKSHAFT POSITION / ENGINE SPEED SENSOR is the factory-engineered signal source your 1997–1998 12-valve 5.9L Cummins depends on for precise RPM and crankshaft position data. Located near the engine timing gear housing, this sensor delivers critical engine speed information to the PCM, ensuring proper fuel delivery, smooth idle stability, and reliable starting performance.
When this sensor begins to fail, classic 12-valve issues—hard starting, intermittent stalling, erratic tach readings, and even no-start conditions—quickly appear. Replacing it with a genuine Cummins 3923129 sensor guarantees correct calibration, OE-grade signal quality, and long-term reliability. No aftermarket unit matches the OEM electronics, shielding, or metal-core construction.
Key Features & Advantages
- Genuine Cummins OEM crankshaft position / engine speed sensor.
- Restores stable RPM signal essential for correct fuel timing and starting.
- Eliminates “no-start,” random stall, and tachometer dropout issues.
- Exact factory connector, mounting geometry, and calibration.
- Designed to withstand vibration and extreme diesel operating conditions.
Fitment
This Cummins genuine sensor fits the following applications:
- 1997 Dodge Ram 2500 5.9L 12-valve Cummins
- 1997 Dodge Ram 3500 5.9L 12-valve Cummins
- 1998 Dodge Ram 2500 5.9L 12-valve Cummins (mechanical P-pump only, pre-24V)
- 1998 Dodge Ram 3500 5.9L 12-valve Cummins
Engine: 5.9L 12-Valve 6BT (Pre-ISB)
Sensor Location: Timing gear housing / crank position pickup
Connector: OE 2-pin harness
Cross-Reference (ID Only)
- Cummins: 3923129 (primary)
- Cummins superseded: 3920687
- Mopar dealer reference: 5086993AA
Cross-references are for identification only. Always verify by VIN or ESN.
Related Genuine Cummins Parts (Working Internal Links)
- CUMMINS 3937111 FRONT CRANKSHAFT SEAL SERVICE KIT – 5.9L (1989–2007)
- CUMMINS 3804899 OEM FRONT CRANKSHAFT SEAL – 5.9L / 6.7L CUMMINS
- CUMMINS 3920706 OEM EXPANSION PLUG – TURBO DRAIN (5.9L / 6.7L)
Installation Notes
- Inspect the wiring harness for chafing—common on older 12-valves.
- Clean mounting surface to ensure proper sensor depth and signal pickup.
- Torque to OEM spec; overtightening can distort signal accuracy.
- After installation, verify tach readings and ensure no P0340/P0336 codes reappear.
Specifications for cummins 3923129
| Specification | Detail |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Part Number | 3923129 |
| Sensor Type | Crankshaft Position / Engine Speed Sensor (CPS) |
| Engine Compatibility | 1997–1998 5.9L 12-Valve Cummins (6BT) |
| Connector Type | OEM 2-Pin Connector |
| GTIN | Not published by Cummins |
| UPC | Not published by Cummins |
| Shipping Weight | Approx. 1 lb |
| Shipping Dimensions | 3" × 3" × 2" (approx.) |
| Shipping Method | Standard ground / small parcel |
| Cross-Reference | Cummins 3923129, Cummins 3920687, Mopar 5086993AA |
| E-Codes / Emissions | Not specified (mechanical 12-valve application) |
| Prop 65 Warning | This product may expose you to chemicals known to the State of California to cause cancer or reproductive harm. www.P65Warnings.ca.gov |
FAQ
WHAT ARE THE SYMPTOMS OF A FAILING CUMMINS 3923129 CRANKSHAFT POSITION SENSOR?
Hard starting, intermittent stalling, erratic tach readings, P0340 codes, or complete no-start conditions are common signs of a failing CPS on a 12-valve Cummins.
IS THIS CUMMINS 3923129 SENSOR A DIRECT FIT FOR 1997–1998 TRUCKS?
Yes. This is the correct OEM sensor for 1997–1998 Dodge Ram 2500/3500 with the 5.9L 12-valve mechanical Cummins.
DOES THIS SENSOR REQUIRE PROGRAMMING AFTER INSTALLATION?
No programming or calibration is required. Install, torque properly, and clear any stored codes if present.
SHOULD I REPLACE ANY OTHER SENSORS WHILE SERVICING THIS ONE?
Many owners replace aging engine sensors together, including temperature, MAP, and sealing components such as the front crankshaft seal (3804899) to prevent future downtime.
