Dodge P1390 Code: CKP/CMP Synchronization Error – Diagnosis and Solutions

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The P1390 code on Dodge vehicles (Ram, Charger, Challenger, Durango, etc.) indicates a critical misalignment between the crankshaft (CKP) and camshaft (CMP), compromising ignition and injection control. Without intervention, this fault can cause irreversible engine damage.


🚨 Immediate Symptoms

  1. Engine fails to start or suddenly stalls.
  2. Severe misfires and power loss under load.
  3. Flashing “Check Engine” light + related codes (P0016, P0340).
  4. Grinding/Clicking noises near the timing cover (loose chain).

🔧 Dodge-Specific Causes

  1. Stretched timing chain (common on Hemi V8 > 100,000 km).
  2. Hydraulic tensioner failure (internal leak or blockage).
  3. Faulty CKP/CMP magnet (cracked or demagnetized).
  4. Damaged reluctor wheel (missing teeth or corrosion).
  5. Low oil pressure (worn pump, clogged filter, old oil).

🔍 Step-by-Step Diagnosis

  1. Check oil pressure:
    • Minimum required: 10 psi at idle, 35+ psi at 2,000 RPM (Use Mopar 4902081AA gauge).
  2. Inspect timing chain:
    • Access via side cover (models: Ram 1500 5.7L Hemi, Charger R/T).
    • Check for stretch (misaligned marks > 6°) and guide condition.
  3. Test sensors:
    • CKP: Resistance 800–1300 Ω (typical Hemi 5.7L value).
    • CMP: AC 0.5–5V signal on oscilloscope.
  4. Advanced Mopar scanning:
    • Use WiTECH or DRB III to analyze CKP/CMP misalignment (> 3° = fault).

🛠️ Recommended Repairs (With Mopar References)

Faulty Component Solution Recommended Dodge Parts
Timing chain Replace full kit (chain + tensioners + guides) Mopar 68164189AA (Hemi 5.7L)
CKP Magnet Replace (air gap: 0.5–1.5 mm) Mopar 56027866AB (Ram 1500)
CMP Magnet Clean or replace Mopar 4894022AB (Charger 3.6L)
Reluctor wheel Inspect crankshaft rotor (replace if scratched/missing teeth) Mopar 4668272AB

⚠️ Critical Warning:
Hemi and Pentastar engines are interference engines! Desynchronization causes piston-valve collision. Stop the engine immediately if abnormal noises occur!


💡 Key Post-Repair Procedures

  1. Timing alignment:
    • Specific Mopar tools: Crankshaft lock 10238 + Camshaft lock 10243.
  2. ECU reset:
    • Clear codes via WiTECH + perform sensor relearn.
  3. Oil control:
    • Use 5W-20/5W-40 Full Synthetic (MS-6395 standard) + Mopar filter 5281090AB.

📊 Technical Sheet

Parameter Value
OBD2 Code P1390
Definition “Crankshaft/Camshaft Correlation Error”
Sensitive Models Ram 1500, Durango, Charger, Challenger (2005–2020)
Urgency MAXIMUM (engine failure risk)

Comparison of Recurring Issues by Model

Model Common Failure Solution
Ram 1500 5.7L Hemi Leaking hydraulic tensioner Mopar chain kit 68164189AA
Charger 3.6L V6 CMP magnet flooded with oil Replace Mopar 4894022AB
Durango 4.7L V8 Oxidized reluctor wheel (moisture) Change rotor Mopar 4668272AB

Conclusion

The P1390 code on Dodge indicates a highly critical timing fault. The primary causes are:

  1. Timing chain wear (especially on Hemi V8),
  2. CKP/CMP magnet failure (sensitive to oil leaks),
  3. Insufficient oil pressure.

Recommended Actions:

  1. Urgently check oil pressure and chain play.
  2. Replace faulty components with Mopar parts to ensure compatibility.
  3. Perform precise timing alignment with dedicated tools and reset the ECU via WiTECH.
    Do not start the engine again – have the vehicle towed to a certified Mopar technician. Ignoring this code can lead to engine destruction (cost: $5,000+).

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