Honda P3497 Code: Cylinder Deactivation System Bank 2 (Honda VCM)
Honda's Variable Cylinder Management on the front cylinder bank didn't behave the way the PCM commanded.
At a glance
Severity: Moderate
- Meaning
- Cylinder Deactivation System Bank 2 (Honda VCM)
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $60–$1,100
- DIY difficulty
- Moderate
Honda V6 engines with Variable Cylinder Management (VCM), found in the Accord V6, Odyssey, Pilot, Ridgeline and several Acura models, shut down cylinders at light cruise by using oil pressure to unlock rocker arms so their valves stay closed. On these engines bank 2 is the front cylinder head, next to the radiator. A VCM spool valve on each head sends oil to the rockers, and a rocker arm oil pressure switch next to it tells the PCM whether pressure actually arrived. P3497 sets when the front bank's switch reports something that doesn't match the command, such as pressure when none was requested, or none when it was. Low or degraded oil, a failing switch and a clogged spool valve screen account for most cases.
Can I keep driving? The PCM usually disables VCM and runs on all six cylinders, so the car drives fine but uses more fuel. If the engine shakes, misfires or the check engine light flashes, reduce speed and have it checked right away, and check the oil level before any long trip.
How to read P3497
- P Powertrain
- 3 Generic (SAE)
- 4 Auxiliary emission controls
- 97 Specific fault
Symptoms
- Check engine light on, ECO indicator no longer appearing at cruise
- Lower highway fuel economy because VCM stays off
- Rough idle or shudder, sometimes with misfire codes
- Oil level below the add mark on the dipstick
- Oil seeping around the front-head oil pressure switch connector
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Low engine oil level from consumption, or overdue or wrong-grade oil
- Front-bank rocker arm oil pressure switch failed or leaking into its connector
- Clogged filter screen under the front VCM spool valve
- Front VCM spool valve sticking or its solenoid failing
- Wiring or connector fault at the switch or spool valve
- Excess oil pressure on cold starts, such as a faulty oil pump relief valve
- Rocker arm synchronizing pin sticking inside the head
Diagnosis step by step
Check the oil level and grade
Read the dipstick on level ground with the engine off for a few minutes. These engines are specified for thin oil, usually 0W-20; if the level is low or the oil is overdue, change oil and filter with the correct grade, clear the code and drive before going further.
Tools: Flashlight
Compare switch status with the command
With a Honda-capable scan tool, watch the VCM spool valve command and the front rocker arm oil pressure switch status while driving at light cruise. The switch should follow the command; if it reports pressure with VCM off, or no change when VCM engages, note which.
Tools: OBD-II scanner
Swap the front and rear switches
The rocker arm oil pressure switches on the two heads are usually the same part. Swap them, clear the codes and drive: if the fault moves to bank 1 and sets P3400, the switch is bad; if P3497 stays, look at the oil supply or spool valve.
Tools: Screwdriver
Inspect the spool valve and its screen
The front VCM spool valve is bolted to the front cylinder head. Remove it, check the fine mesh screen in its gasket for sludge, and check its connector for oil. Replace the gasket and screen rather than trying to clean it.
Tools: Screwdriver, Flashlight
Check misfires and spark plugs
Look for stored misfire codes and pull the plugs from the front bank. Oil-fouled plugs point to the oil consumption these engines are known for, which also explains a repeatedly low oil level.
Tools: Spark plug socket, OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Oil and filter change with 0W-20 | Yes | $60–$120 |
| Replace front rocker arm oil pressure switch | Yes | $60–$250 |
| Front VCM spool valve gasket and screen | Yes | $100–$300 |
| Replace front VCM spool valve assembly | No | $300–$700 |
| Oil pump relief valve repair (pan removal) | No | $500–$1,100 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Honda
Honda V6 engines with VCM are widely reported to burn oil and foul spark plugs on the cylinders that get deactivated, which can lead to misfires and engine vibration. A low oil level from that consumption is a common trigger for P3497, so check the dipstick between oil changes.
Emissions / smog test impact
Will fail
An active P3497 keeps the check engine light on and fails OBD-based emissions tests. Once repaired, drive a few days so the misfire-related monitors run and report ready.
Frequently asked questions
What's the difference between P3400 and P3497 on a Honda?
They're the same VCM fault on different cylinder heads. P3400 is bank 1, the rear head near the firewall, and P3497 is bank 2, the front head near the radiator. Having both at once points to a shared cause such as oil level or oil pressure.
Will an oil change fix P3497?
Often, when the oil was low or overdue. If the code returns with fresh oil at the right level, test the front rocker arm oil pressure switch and inspect the spool valve screen.
Should I install a VCM disabler?
Devices that keep VCM from engaging are sold for these engines, but they don't fix P3497 and may affect emissions compliance. Repair the oil, switch or spool valve fault first.
Can P3497 damage the engine?
The code itself doesn't, but its causes can. Running low on oil harms the whole engine, and misfires from stuck rocker arms or fouled plugs can overheat the catalytic converter. Check the oil right away.
Sources
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy