Troubleshooting the check engine light for 2002 Toyota Tundra by any do it yourselfer should be easy if you use an OBD2 scanner. Just remember to specify that the scanner you have will work for this vehicle. In some generic scanner, the Toyota codes will not work because the scanner is only good for domestic vehicles like GM, Dodge and Ford.

Diagnostic Troubleshooting Specs:

Diagnostic connector is located on the right of the steering column just below the dash. A scanner can be hooked up to the diagnostic connector to retrieve the fault code.

Diagnostic fault codes are stored using 2-trip detection system whereby the fault code will not show up the first time it is detected but shows on the 2nd time the code shows up. This usually applies to generic scanner but not on Toyota scanner.

Fault code that are scanned can be seen using a “Freeze Frame Data”. This system will show the actual condition of the engine when the fault code appears. This conditions includes engine temp, engine speed, vehicle speed and other factors leading to the code. However, if there are multiple codes store in the memory, only the first code will show in the freeze frame data.

Diagnostic TIPS:

The most common obd2 problem on this 2002 Toyota Tundra are the oxygen sensors. This applies to the upstream sensors located in the exhaust manifold and the downstream oxygen sensors located after the catalytic converters. If your vehicle has mileage under 100k, try contacting your Toyota dealer because sometimes, those sensors are covered by warranty. In case you need to fix it yourself:

1.) Measure the oxygen sensor signal voltage as soon as the engine warms up. It should fluctuate between 0.1v to 0.9v or around 0.4v to 0.6v difference. The rear CAT sensors difference is much closer which is around 0.1v to 0.3v. Any sensors out of these ranges should be replaced.

2.) If the oxygen sensors are covered in the warranty, sometimes the exhaust manifolds are covered too especially if the manifolds are leaking which can cause the upstream sensors to fail again if not replaced. Ask this coverage when dealing with Toyota dealers since this job is very expensive if you fix it yourself.

Thanks!

This entry was posted on Sunday, April 20th, 2008 at 4:03 am and is filed under Check Engine Light FIXES. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.