The default code P1399 is a common issue on Acura vehicles (particularly Honda/Acura models from 2000-2010). It indicates a malfunction in the Variable Valve Timing Control (VTC) system. This system optimizes engine performance and efficiency by adjusting camshaft timing in real time.
Here is a comprehensive guide to understanding and resolving this issue.
❌ Common Symptoms
- Hard starting (especially when cold): metallic rattling noises upon startup.
- Unstable idle: engine vibrations or hiccups.
- Loss of power: weak acceleration, especially at low RPM.
- Check engine light on: with stored code P1399.
- Increased fuel consumption.
🔧 Possible Causes
- Faulty VTC solenoid (most common cause): clogging or electrical failure.
- Clogged oil filter or degraded engine oil: insufficient pressure to operate the VTC system.
- Loose timing chain: premature wear of the tensioner or chain.
- Faulty Camshaft Position Sensor (CMP).
- Wiring problem: short circuit or corroded connector.
- Low oil pressure: worn oil pump or leak.
🔍 Diagnostic Steps
- Check engine oil:
- Level and quality (replace if black or old).
- Use a quality 5W-30 or 0W-20 oil (e.g., Honda/Acura Genuine Oil).
- Inspect the VTC solenoid:
- Disconnect the electrical connector and measure resistance (normal value: 14–30 Ω).
- Clean the solenoid with brake cleaner to remove deposits.
- Inspect the oil filter: Replace if necessary (prefer an OEM filter).
- Test oil pressure: Using a pressure gauge (target: ≥ 35 psi at idle).
- Scan real-time data:
- Check CMP sensor values and VTC timing angles via an advanced OBD2 tool (e.g., HDS).
- Examine the electrical circuit: Look for damaged wires or corrosion on the solenoid connector.
🛠️ Recommended Repairs
- Replace the VTC solenoid:
- Recommended part: OEM Solenoid 15860-R70-A01 (approximately $80–150).
- Location: On the engine block, near the crankshaft.
- Change oil and filter:
- Synthetic 5W-30 oil + Honda/Acura filter (e.g., 15400-PLM-A02).
- Update timing chain alignment (if necessary):
- Check chain tension and replace the chain tensioner if excessive play.
- Replace the CMP sensor (associated code P0340/P0341): Part 37870-PND-A01.
- Reset the ECU: Clear the code with an OBD2 scanner after repair.
⚠️ Warning: On certain models (e.g., Acura TL 2004–2008, MDX, RDX), hard cold starting accompanied by rattling may indicate a design flaw in the VTC system. An ECU software update is sometimes required (consult a dealership).
💡 Prevention Tips
- Change oil every 8,000 km max: The VTC system depends on oil pressure.
- Use OEM parts: Generic solenoids often cause recurring issues.
- Professional diagnosis if in doubt: A Honda HDS scanner allows for in-depth testing (e.g., checking live VTC parameters).
📊 Quick Reference Sheet
| Code | P1399 |
|---|---|
| Definition | VTC System Problem |
| Affected Acura Models | TL, MDX, RDX, TSX, CL (2000–2015) |
| Most Common Solution | Replace VTC solenoid + oil change |
Conclusion
The P1399 code on Acura points to a failure in the variable timing system, often resolved by cleaning or replacing the VTC solenoid and a thorough oil change. Ignoring this issue can lead to premature timing system wear or significant power loss. Prompt action preserves engine health and restores original performance.
For complex cases, consult a Honda/Acura specialist mechanic equipped with the HDS tool!