🚨 Diagnostic Profile
Vehicle Make: Chrysler
Description: 24X Reference Circuit High Voltage. The ECM is reading a voltage on the 24X crankshaft position reference circuit that is above the expected operating range. This condition is commonly associated with DTC P0338 (Crankshaft Position Sensor A Circuit High). Confirm the exact DTC set on the specific model and year before proceeding.
🚨 Repair Difficulty Tier
Tier: [Intermediate]
Sensor replacement is straightforward, but isolating a high-voltage fault in the reference circuit requires a digital multimeter, wiring diagram access, and the ability to check for shorts to voltage or open-circuit conditions in the harness and connectors.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Verify battery voltage and charging system output are within specification at the time of the fault (battery should read approximately 12.4-12.6V at rest, charging system should produce 13.5-14.7V with engine running).
- Scan for all stored and pending DTCs, and record freeze frame data including RPM, engine coolant temperature, and any no-start or stall history.
- Visually inspect the 24X crankshaft position sensor connector, typically located on the engine block near the crankshaft pulley/harmonic balancer area or at the bell housing depending on engine family (3.6L Pentastar, 5.7L HEMI, or 2.4L/2.0L four-cylinder applications each have distinct sensor mounting locations), for corrosion, bent pins, spread terminals, moisture, or oil contamination.
- Inspect the sensor wiring harness along its full route for chafing, pinched sections, heat damage, or rubbing against brackets, the serpentine belt, or exhaust components.
- Check the sensor mounting bolt torque and air gap condition, and confirm the reluctor/tone wheel is clean, free of metal debris, and undamaged.
Step 2: Diagnostic Verification
- Back-probe the 24X sensor signal circuit at the ECM connector and measure voltage with the key on/engine off, then with the engine cranking. On most Chrysler Hall-effect type 24X sensors, the signal should toggle cleanly between a low state (near 0V) and a high state (near sensor reference voltage) with no erratic spikes above the expected reference ceiling.
- Measure sensor supply and ground circuits for correct voltage and resistance. Most Chrysler crank sensors are 3-wire Hall-effect units fed by a 5V or 8V reference circuit from the PCM; confirm reference voltage is present at the sensor connector with the sensor disconnected and verify ground continuity reads less than 5 ohms to chassis ground.
- If the sensor is a variable-reluctance (2-wire AC-output) type rather than Hall-effect, perform a resistance check across the two signal terminals and compare the reading to the OEM factory service manual specification for that specific engine and model year, as values vary by application.
- Check the signal circuit for a short to voltage by measuring at the ECM connector with the sensor disconnected, key on, referencing the factory wiring diagram for the exact circuit identification and connector pinout for this model year and engine combination.
- If available, use a lab scope to view the 24X waveform and compare amplitude, duty cycle, and consistency through the RPM range; look specifically for voltage spikes, dropouts, or noise coinciding with the P0338 high-voltage fault trigger.
Step 3: Resolution & Reset Process
- Repair any identified harness damage, corroded terminals, or poor connections using OEM-spec weatherproof splice connectors and heat-shrink, and replace the crankshaft position sensor if it fails resistance, reference voltage, or signal pattern testing.
- Clear all DTCs using a scan tool capable of bi-directional communication (such as a Snap-on, Autel, or Chrysler-specific wiTECH interface) and perform a crankshaft/camshaft sync relearn or Crank Position System Variation Learn procedure if called for in the service information for this model, as some Chrysler PCMs require this relearn after sensor replacement to prevent re-triggering sync-related codes.
- Road test or run the engine through multiple idle, acceleration, and deceleration cycles to verify the DTC does not return, and confirm normal idle quality, cranking behavior, and overall driveability with no hesitation or stalling.
- Re-scan the system after the test drive to confirm no pending or stored codes have reset, and verify PCM freeze frame data is clear.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Crankshaft position sensor (24X reference) — OEM or OEM-equivalent (Mopar, Standard Motor Products, or Delphi), verify exact part number against VIN at a dealer parts counter or parts catalog for the specific engine and model year
- Connector repair kit, pigtail harness, or weatherproof splice connectors, if harness damage is found
- Dielectric grease, electrical contact cleaner, and mounting hardware/bolts as needed
- Scan tool with bi-directional control and crank relearn capability (aftermarket professional-grade tool or Chrysler wiTECH/StarMOBILE dealer-level software) if the PCM requires a formal sync relearn procedure
Average Component Price:
- Crankshaft position sensor: approximately $35-$120 depending on engine family and OEM vs. aftermarket sourcing
- Harness or connector repair materials (pigtail, splice kit, terminals): approximately $20-$75
- Scan tool diagnostic use or dealer programming/relearn session fee: approximately $100-$180 per hour if outsourced to a dealership or specialty shop
Estimated Labor Hours:
- Diagnostic verification (DTC retrieval, visual inspection, circuit and waveform testing): approximately 0.5-1.5 hours
- Sensor replacement and relearn procedure: approximately 0.5-1.2 hours depending on engine accessibility (some applications require front engine mount or serpentine belt removal for sensor access)
- Harness repair, if required: approximately 0.5-1.5 hours depending on damage location and accessibility