P3449 tells you the engine computer lost continuity in the circuit to the cylinder 7 deactivation solenoid. Chrysler documents it twice for the 5.7 L Hemi with MDS: a 2025 bulletin for the 2023 RAM 1500 eTorque lists it next to a cylinder 7 misfire (P0307) and fixes it with new PCM software, and a STAR case names P3449 first when the driver-side manifold heat shield has worn through the MDS harness at the rear of the cylinder head. GM uses the code on AFM V8s (L86, LT4 Corvette) and on the DFM L84, flagging more than 200 kohm in the off state, 20 of 25 samples, Type B. P3451 and P3452 report shorts, P3450 a mechanical fault on cylinder 7.
Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
Cylinder 7 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine lamp on
- Engine stays in eight-cylinder mode
- Rough idle or misfire on cylinder 7 (P0307) on the 5.7 L Hemi
Most likely causes
- MDS harness at the rear of the driver-side head worn through by the manifold heat shield (5.7 L Hemi)
- Cylinder 7 solenoid coil open
- Solenoid connector loose or corroded
- PCM calibration needing an update (Chrysler TSB 18-002-25)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P3449 means
- P: Powertrain: engine and transmission
- 3: Generic or manufacturer code, depending on the range
- 4: Emissions
- 49: Specific fault in that system
Frequently asked questions
Can I keep driving with code P3449?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P3449?
The most common causes are: mDS harness at the rear of the driver-side head worn through by the manifold heat shield (5.7 L Hemi); cylinder 7 solenoid coil open; solenoid connector loose or corroded.
Related codes
- P3450Cylinder 7 Deactivation/Intake Valve Control Performance
- P3451Cylinder 7 Deactivation/Intake Valve Control Circuit Low
- P3452Cylinder 7 Deactivation/Intake Valve Control Circuit High
- P3453Cylinder 7 Exhaust Valve Control Circuit/Open
- P3441Cylinder 6 Deactivation/Intake Valve Control Circuit/Open
- P3400Cylinder Deactivation System Bank 1
- P3497Cylinder Deactivation System Bank 2
- P0307Cylinder 7 Misfire Detected
Sources
- law.cornell.edu: 13 CCR 1968.2
- static.nhtsa.gov: MC 11013168 0001
- static.nhtsa.gov: MC 10176548 9999
- gsi.ext.gm.com: 19OBDG03B Diagnostics
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.