Acura Engine Light or Long Start? EVAP Causes & Fixes

Acura Engine Light and a Long Start: Check the EVAP System

A check engine light together with a long crank, especially right after filling up, is a common Acura complaint. The cause is usually in the EVAP (evaporative emission) system, most often the canister vent shut valve or the purge valve. This guide combines our posts for the CL, MDX, RL, RLX, TL, TLX and ZDX. The EVAP layout differs by generation, but the faults, codes and tests are the same.

Check for recalls for your vehicle, and see every code in our P0400–P0499 code list.

How the EVAP System Works

Fuel vapour from the tank is stored in a charcoal canister. When the engine is running, the purge valve opens and lets the engine burn that vapour. The canister vent shut valve (canister vent solenoid), usually near the canister by the fuel tank, closes so the system can seal itself and test for leaks.

Symptoms

• Check engine light, often with code P1457.
• Long crank after refuelling: a purge valve stuck open lets fuel vapour flood the intake.
• Fuel smell around the car.
• The pump keeps clicking off when you fill up, a sign the vent side is blocked or stuck closed.
• A loose, worn or missing gas cap can cause the same light, so start there.

Common OBD Codes

• P1457: Honda/Acura EVAP system leak (canister side)
• P0441: incorrect purge flow
• P0442: small leak detected
• P0446: vent control circuit
• P0455: large leak detected
• P0456: very small leak detected
• P0496: flow during non-purge (often a purge valve stuck open)

Troubleshooting

1. Check the gas cap: make sure it clicks, the seal is not cracked, and replace it if in doubt. Clear the code and drive for a few days.
2. Scan for codes and note the freeze-frame data.
3. Inspect the EVAP hoses, canister and connectors near the fuel tank for cracks, damage or loose fittings.
4. Test the vent shut valve: unplug it, check its resistance against the service manual, apply 12 volts and listen for a click, and check that it holds vacuum when closed.
5. Test the purge valve: unpowered, it should hold vacuum. If air passes through it with no power applied, it is stuck open, the classic cause of a long start after filling up.

Replacing the Valve

1. Disconnect the battery.
2. Unplug the electrical connector and note how the hoses are routed.
3. Remove the valve from its bracket and fit the new one in the same position.
4. Reconnect the hoses and connector, then the battery.
5. Clear the codes and confirm the light stays off over the next few drives.

When to Bring It In

If the code comes back and the parts test fine, the leak needs a smoke test to find it. Radman Auto Repair at 321 Rexdale Blvd, Etobicoke, smoke-tests EVAP systems and fixes the actual leak. See P0455 EVAP leak diagnosis and check engine light after getting gas.

Frequently Asked Questions

Why does my Acura take long to start after I fill up with gas?

Usually a purge valve stuck open. Fuel vapour from the tank floods the engine when it is off, so it cranks longer before it starts. Testing the purge valve confirms it.

What does code P1457 mean on an Acura?

It is a Honda/Acura EVAP leak code for the canister side of the system. Common causes are a faulty canister vent shut valve, a cracked hose or canister, or a gas cap that does not seal.

Can a loose gas cap turn on the check engine light?

Yes. A loose, worn or missing cap lets the EVAP system fail its leak test. Tighten or replace the cap, and the light should go out after a few drives if that was the cause.