P00400: “A Camshaft Position Slow Response (Bank 2)”

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🔧 Code Meaning

P00400 (Bank 2) — “Camshaft Position ‘A’ Slow Response.”

This means the intake camshaft on bank 2 (the side of the engine without cylinder #1) isn’t adjusting as fast as the ECM/PCM expects when it commands a timing change.

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⚙️ How the System Works

Modern engines use VVT (Variable Valve Timing) to adjust camshaft timing. The ECM controls oil control solenoids (OCV/VVT solenoids) to send oil pressure to cam phasers that advance or retard timing.

When the ECM commands a change and the camshaft doesn’t respond quickly enough, this code sets.

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🧭 Possible Causes

Type Common Causes

Oil-related • Dirty or low engine oil <br>• Wrong oil viscosity <br>• Blocked oil passages <br>• Sludge in VVT system

Electrical • Faulty camshaft position sensor (Bank 2 Intake) <br>• Faulty VVT solenoid (OCV) for Bank 2 <br>• Damaged wiring or connector (corrosion, open, short)

Mechanical • Sticking or worn cam phaser <br>• Stretched timing chain or worn tensioner <br>• Improper timing (chain jumped a tooth)

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🧰 Diagnostic Steps

1. Check Engine Oil

Verify correct level, viscosity, and cleanliness.

Dirty or thick oil can slow cam phaser response.

.2 Visual Inspection

Inspect VVT solenoid connector and wiring for corrosion or damage.

Unplug and check resistance (usually around 6–12 ohms — depends on vehicle).

3. Test the Camshaft Solenoid (OCV)

Command it ON/OFF using a scan tool (if available).

Listen for a click or measure operation with a multimeter.

4. Check Camshaft Position Sensor (Bank 2 Intake)

Verify signal using a scope or scan tool (compare with Bank 1).

5. Oil Flow Check

Remove the OCV and inspect the oil passages for sludge or debris.

6. Mechanical Timing Check

If oil and electronics are fine, check for timing chain stretch or cam phaser sticking.

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🧾 Repair Tips

Replace or clean VVT solenoid (OCV) if sticking or clogged.

Change oil & filter using manufacturer-recommended viscosity.

If persistent, inspect/replace cam phaser or timing chain components.

Always clear code and recheck after test drive.

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🛠 Example Quick Fix Path (Common Case)

1. Oil dirty → Perform engine flush + oil/filter change.

2. Still slow → Clean or replace Bank 2 VVT solenoid.

3. If still showing → Inspect cam phaser/timing chain.

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