I have been working on a lexus ES350 I'm getting codes p0...

Q: I have been working on a lexus ES350 I'm getting codes p0300 p0174 and c342d and can't figure out what the problem is, can u help?

asked by on October 31, 2017

It started as code p0301 so I replaced cool on cylinder 1 and all spark plugs and boots since it was such a big job having to take intake off to access cylinders 1,3, &5. Then had to go back and fix camshaft position sensor bc of one wire pulling loose. And still getting code p0300 along with p0171 so I replaced pcv valve bc it had a small leak and I'm still getting codes p0300, p0141, p0355 and also this code c342d. Please help...
My car has an automatic transmission.

C342d relates to faults in the throttle position sensor (TPS) or the idle air control valve (IAC). Check the wiring to the TPS sensor and the IAC valve and test for high resistances which will show up as voltage drops. P0355 can be caused by wiring faults but also by a faulty IAC valve so the IAC should be looked at closely. The TPS sensor response can be tested using a real time scan tool. With regard to the other codes, two common denominators across those codes are oxygen sensors and vacuum leaks. To resolve all of these codes, a real time scanner is necessary to look at actual engine operating parameters, for example the response of the oxygen sensors, the integrity of the heater circuit, and, with regard to vacuum leaks, to see if such leaks perhaps show up in measured fuel trims that are read off of a scanner. To have the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, the recommended service to get your issue(s) resolved is a check engine light diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Knocking noise when turning at slow speeds and braking

Faulty outer CV axle joints can make a knocking noise on turning. If the identical noise also occurs in park, it may be that you have multiple sources of the knocking. An option for you is to schedule a front...

Airplane sound while applying the brakes.

Hello, thank you for writing in. The noise you are hearing is very likely caused by the brake pads wearing down over time like they are designed to do. You are hearing the metal of the brake calipers rubbing on...

How long can I drive my car with the engine light on?

Hi there. It is no good to drive a vehicle with the engine light on. The engine light is on for a sensor has picked up something that is not functioning or operating correctly. Check the computer with a scanner...

Related articles

A Buyer's Guide to the 2012 Lexus GS450h
The The 2012 Lexus GS450h is for those who want to drive a hybrid, but would prefer to still enjoy a luxurious and safe ride. Fortunately, as this sedan proves, going the hybrid route doesn’t have to mean you lose...
A Buyer's Guide to the 2012 Lexus IS
If If you haven’t heard of the 2012 Lexus IS, you’re not alone. This sports sedan is incredibly underappreciated. However, that doesn’t mean it’s not worth considering for your next car. Key Features The 2012 Lexus IS can be purchased...
Top 10 Factors to Consider When Buying a Luxury Car
The The idea of owning a luxury car is appealing. The glossy paint, swoopy lines, and prestigious badges speak of the owner’s success in life, while the interior opulence offers scented leather surfaces, high-tech telematic devices, and all the creature-comfort...