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2000 Lexus GS 300 Repair Question


Topics covered: Sensor, Wiring, Click.
Mileage: 124,000 miles.

Asked on February 14, 2012

My car doesnt idle when you start in the morning so engine shakes till it heats up then it stops, secondly when i turn on the a/c the rpm goes down

Replied on September 14, 2012

P0120 - Throttle Position Sensor (TPS) circuit malfunction.

P0161 - Heated HO2S sensor heater circuit, can be either a bad sensor or missing power supply.

P0300 - Random cylinder misfiring detected. Possibly related to P0120 and P1120.

P0450 - EVAP pressure sensor sensor malfunctioning.

P1120 - Accelerator Position sensor ciruit malfunction.

P0120 and P1200 are the main problems you need to address before you go to others. Both are critical for engine performane and idle controls.

These problems were not mentioned in earler post so I guess they were a result of you working on the vehicle. Recheck the wiring connections and ensure they are clean and secure. Ensure connectors are correctly plugged in and you would need to perform diagnostics if you can't find any faults, which would be easier if you have a scan tool.

Tiny Answered by KHLow2008 (expert)
39,964 answers provided
Replied on September 14, 2012

I have a scan tool, anytime i erase them, they seem to come back again after driving for a while, i would do suggested and i hope something good comes out of it.

Tiny Response from martinkodua
1 question asked
Replied on September 14, 2012

do you have a diagram of how to connect to O2 sensors? maybe i may have them in the wrong connectors

Tiny Response from martinkodua
1 question asked

Replied on September 14, 2012

Here are the schematic for the O2 sensors. Ensure you have battery voltage to the Black/Red wires with ignition switch turned on.

Tiny Answered by KHLow2008 (expert)
39,964 answers provided
Replied on September 14, 2012

Thank you very much, I would print this and send to my electrician to help me out. You have helped me since i started fixing this car and i dont want to be ungrateful so I would like to donate something but unfortunately am in Ghana but my brother is in the US. Do you have paypal? I can authorize him to donate $20 for now. Also is it possible to send me any other schematics you think i may need by email, I cant seem to download this to print. if its possible my email address is martinkodua@yahoo.co.uk

Tiny Response from martinkodua
1 question asked
Replied on September 14, 2012

Yes, you can donate via Paypal. Tell whomever is doing this to click this post and click the " Upgrade Question " link to proceed with the donation.

I will send the engine management wiring schematic set to your email.

Thank you for the donation.

Tiny Answered by KHLow2008 (expert)
39,964 answers provided

Replied on September 14, 2012

Am doing this myself so if you can give me your paypal address, i would let my brother donate the $20 on my behalf.

Tiny Response from martinkodua
1 question asked
Replied on September 14, 2012

My internet connection to our database is rather lagging presently so it might be a while before you get the documents.

Tiny Answered by KHLow2008 (expert)
39,964 answers provided
Replied on September 16, 2012

Please do you have the schematics of the vacuum system for the car so i can cross check all hoses to be sure they are in the right places. Thank you

Tiny Response from martinkodua
1 question asked
Replied on September 16, 2012

Refer to my February 15 reply for the vacuum diagrams.

Tiny Answered by KHLow2008 (expert)
39,964 answers provided