# RAV4 2013 Emission test fail **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** rav4, toyota\ **Created:** [September 16, 2023, 4:46am UTC](https://community.cartalk.com/t/rav4-2013-emission-test-fail/192917 "2023-09-16T04:46:41Z")\ **Posts on this page:** 1\ **Showing post:** 7
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 16, 2023, 11:03pm UTC](https://community.cartalk.com/t/rav4-2013-emission-test-fail/192917/7 "2023-09-16T23:03:54Z")
Good ideas above. I’m guessing a fuel trim test has already been done, suggest to ask your shop for that data and post it here. It would be hard to believe a shop would remove the cylinder head and clean the tops of the pistons without first doing a fuel trim test. If the fuel trim tests says the fuel mixture is too rich, likely causes are - Engine coolant temp sensor is faulty (perhaps this is actually the “water pressure sensor” referenced by OP) - Fuel rail pressure is too high - Fuel injector(s) leaking - MAF sensor is faulty or dirty - Engine air filter clogged - Evap system problem, especially purge valve - O2 sensor faulty - Exhaust system not flowing freely - Engine cylinder compression is too low (internal engine problem) Higher octane fuel is unlikely to help. Suggest to give up on that idea. A fuel injector cleaning procedure or treatment might help though. It doesn’t pertain to the exactly same problem, but it might still be helpful to read through the following thread. > [@92 Corolla High HC Emissions](https://community.cartalk.com/t/92-corolla-high-hc-emissions/84622): > > Every two years here in Calif I have to do an emissions test on my 92 Corolla (4AFE engine). Every year I just barely pass the HC limit. I just had this test done last week. So I should say “Every year I barely pass, until now”. Here’s the emissions data showing I failed: HC’s at 15 mph measures 140, max allowed is 130. FAILED. HC’s at 25 mph easily passes with 67 measured, max allowed 105. PASSED. CO and NO easily pass at both speeds. PASSED. %CO2 =15, %O2 = 0.1 to 0.2 (Not part … --- _[View the full topic](https://community.cartalk.com/t/rav4-2013-emission-test-fail/192917)._