Have you experienced check engine light Camry code 401? You are not alone because this is common fault code for Toyota Camrys especially on models between 96 up to 2002 (with more egr problems occurring on earlier models like those in late 90s). When this code occurs, the main culprit is the egr system which is the exhaust gas recirculating system used to help control engine emission.

This check engine light Camry code 401 stands for:

Insufficient egr Flow detected and is designated by code letters and numbers: P0401

Once detected in your engine, your vehicle will fail the smog emission test and most garages will ask you to fix it first. Lots of drivers trying to save money would be advised to fix it themselves. Why? Because the fix for this is not really difficult. All you need is a vacuum diagram of the egr system so you can identify it’s components.

Here are some quick tests for check engine light Camry code 401:

Manually lift the egr valve pintle rod to activate the egr valve on idle. Engine should start running rough right away or the egr valve is defective. Before replacing, you can remove it and clean the egr vacuum passages or torn rubber diaphragm. Most of the time, it will fix the problem otherwise, it is just a matter of putting a new one from the dealer (stay away from after market egr valve to avoid complications later).

Tip for check engine light Camry code 401:

Most egr fault code problem like this is fixed also by checking the egr vsv valve. This valve has a solenoid which has a mechanical directional passages to divert engine manifold vacuum flow at the egr using ecm commands.

For most Camrys, this is how to test the vsv valve:

Try warming up the engine to operating temperature. Tee into the vacuum hose going to the egr valve and install a manual hand held vacuum guage. Rev the engine to 2500 rpm and hold it. You should see vacuum at the valve. Now using a scan tool, command the vsv to go on and off. The egr valve should be commanded off and restored when turned on. If the egr valve is good but would not follow the scan command, you need a new vsv valve provided the wirings going to the vsv valve are OK. You would need a wiring diagram for the vsv valve so you can verify the vsv wires.

If you have any check engine light Camry code 401 concerns, please let me know.

Thanks!