P0401 code

1999 TOYOTA TACOMA

198,000 MILES • 2.7L • 4 CYL • 2WD • AUTOMATIC

CANNON1349

✓Experienced Mechanic
861 POSTS

P0401 code continues to show up, even after replacing the EGR. Oddly enough the code doesn't show up for a while if mid-grade gas is used.

Jul 15, 2019 at 9:17 PM

SCGRANTURISMO

✓Experienced Mechanic
4,897 POSTS

Hello,

In the diagrams down below I have included for you the factory diagnostic troubleshooting flowchart for Direct Trouble Code(DTC) P0401 for your vehicle. It will require you to use a multi-meter, so I have included this link below for you if you are unfamiliar with how to use one:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Please go through these guides, if needed, and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

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Jul 15, 2019 at 11:20 PM

CANNON1349

✓Experienced Mechanic
861 POSTS

Turned out they left the sensor for the EGR temperature unplugged. Now getting a p0402 code, ironically.

Feb 12, 2020 at 3:32 AM

SCGRANTURISMO

✓Experienced Mechanic
4,897 POSTS

Hello again,

That is ironic and a little funny actually. But, in good spirits, I have included the diagnostic troubleshooting flowchart for your vehicle from the manufacturer for DTC P0402, with generic OBD2 scan tool testing. Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros

Images (Click to enlarge)

Professional Diagram for 2CarPros Members
Click here to log in and view diagram.

Feb 12, 2020 at 7:40 AM