How to Fix Diagnostic Code P1372

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🚨 Diagnostic Profile

Vehicle Make: Chrysler

Description: Crankshaft Position Sensor Circuit Performance. The crankshaft position (CKP) sensor monitors crankshaft rotation and position for ignition timing and fuel injection synchronization. A performance fault indicates the signal is present but is erratic, out of range, or inconsistent with expected timing patterns.

🚨 Repair Difficulty Tier

Tier: [Intermediate]

Sensor replacement is generally straightforward, but wiring diagnosis, reluctor ring inspection, and proper relearn or reset procedures require scan tool access and familiarity with Chrysler diagnostic procedures.

🛠️ Resolution Steps

Step 1: Preliminary Inspection

  • Verify the diagnostic trouble code (DTC) and review freeze frame data for engine RPM, coolant temperature, and operating conditions at fault setting.
  • Visually inspect the CKP sensor connector for corrosion, bent pins, moisture intrusion, or loose seating.
  • Inspect the CKP sensor wiring harness for chafing, heat damage, or pinched sections along its routing path, particularly near the engine block, bellhousing, or exhaust manifold where heat and vibration exposure is highest.
  • Inspect the sensor mounting bolt and bracket for looseness, debris buildup, or damage.
  • Inspect the reluctor ring or tone wheel (integrated into the crankshaft, flexplate, or harmonic balancer depending on engine family) for missing teeth, cracks, metal shavings, or oil contamination.
  • Confirm the sensor air gap is within factory tolerance; on Chrysler Hall-effect or magnetic CKP sensors this is typically a non-adjustable, fixed clearance established by the sensor mounting boss, so focus inspection on correct seating and absence of debris rather than manual gap adjustment unless the service manual for the specific engine family specifies a shim or spacer value.

Step 2: Diagnostic Verification

  • Connect a scan tool and monitor CKP sensor signal data (RPM correlation, sync status, and crank/cam correlation PID if available) live during cranking and idle, comparing to camshaft position sensor data for correlation faults.
  • Check sensor supply voltage at the connector (key on, engine off) using a digital multimeter against a known good ground; Chrysler CKP sensors are typically powered from a 5V or 8V reference circuit or a switched 12V ignition feed depending on sensor type (Hall-effect vs. variable reluctance) — confirm actual reference voltage is present and stable with no unexpected voltage drop.
  • Verify sensor ground integrity by checking for less than 0.2V drop between the sensor ground pin and chassis/engine ground with the circuit under load.
  • Check signal circuit continuity and resistance from the sensor connector to the PCM connector with the harness disconnected at both ends; resistance should read near 0 ohms (typically under 5 ohms) with no continuity to ground or adjacent circuits.
  • Perform a waveform or oscilloscope check of the CKP signal pattern; a healthy signal should show consistent, evenly spaced pulses (square wave for Hall-effect sensors or AC sine wave for variable reluctance sensors) with a clear sync gap corresponding to the missing tooth/reluctor pattern, with no dropouts, noise, or amplitude variation during cranking and across the RPM range.
  • Confirm sensor resistance across its terminals (if variable reluctance type) falls within the manufacturer specification for that engine family using an ohmmeter with the connector disconnected; Hall-effect type sensors cannot be resistance-tested this way and must be verified using the voltage/waveform methods above.
  • Verify the sensor is correctly located per the specific engine family service information, typically mounted near the crankshaft pulley/harmonic balancer, at the bellhousing reading the flexplate/flywheel reluctor, or on the engine block adjacent to the crankshaft — confirm correct part and mounting location for the exact engine application before condemning the component.

Step 3: Resolution & Reset Process

  • Replace the CKP sensor if it fails resistance, signal, or waveform testing.
  • Repair any damaged wiring, corroded connectors, or ground points identified during verification using proper soldering/heat-shrink or OEM-spec splice connectors — avoid butt connectors on sensor signal circuits where possible.
  • Replace or clean the reluctor ring if damaged or contaminated, following Chrysler service procedures for the specific engine (this may require flexplate, flywheel, or balancer replacement depending on where the reluctor ring is integrated).
  • Torque the sensor mounting hardware to the engine-specific factory torque specification found in the official Chrysler service manual for the exact engine family; do not overtighten, as this can crack the sensor housing or alter the fixed air gap.
  • Clear all stored DTCs with a scan tool and, on applicable Chrysler PCM strategies, perform a crankshaft/camshaft correlation relearn or a base idle/PCM adaptive reset procedure per the scan tool’s guided diagnostic routine.
  • Road test the vehicle through multiple idle, acceleration, and deceleration cycles, then recheck live CKP data and confirm no correlation or performance DTCs return.

📦 Parts, Labor, and Budget Estimates

Required Components/Software:

  • Crankshaft position sensor (OEM or OE-equivalent)
  • Sensor connector pigtail or harness repair kit, if required
  • Mounting bolt and O-ring or seal, if required
  • Reluctor ring, flexplate, or harmonic balancer, if damaged
  • Scan tool with bi-directional control, live data streaming, and manufacturer-specific relearn/reset capability (factory-level tool such as Chrysler’s wiTECH preferred for full relearn access)
  • Digital multimeter and automotive oscilloscope

Average Component Price:

  • CKP sensor: approximately $30–$120 (OEM Mopar sensors typically run $60–$110; aftermarket equivalents $25–$60)
  • Harness or connector repair kit: approximately $20–$75
  • Reluctor ring/flexplate/balancer (if damaged): approximately $80–$350 depending on component and engine family
  • Dealer-level diagnostic software/programming access (if independent shop lacks wiTECH subscription): approximately $50–$150 per diagnostic session or sublet fee

Estimated Labor Hours:

  • Diagnostic verification (visual inspection, circuit testing, waveform capture): 0.5–1.5 hours
  • Sensor replacement (labor varies significantly by engine layout/accessibility — some CKP sensors are easily accessible from the top or side of the engine, others require under-vehicle access or partial component removal): 0.3–1.5 hours
  • Reluctor ring, flexplate, or balancer replacement (if required): additional 1.5–4.0 hours
  • Relearn, DTC clearing, and road test verification: 0.3–0.5 hours
  • Total estimated shop time for sensor-only repair: approximately 1.0–2.5 hours; total estimated cost range (parts and labor) for a straightforward sensor replacement: approximately $150–$400; costs increase substantially, potentially $400–$800+, if reluctor ring or flexplate/balancer replacement is required.