nishant11

After winter when I turned on A/C first time on my 2003 TL S it did not work

I do not hear clicking noise when I turn on A/C.

I took it to the mechanic and he checked it and informed me that ECU is not sending out signal to energize A/C relay and that ECU needs replacement.

I would like to know how accurate his diagnosis is and whether this is a known issue?

ECU change and programming is as expensive as transmission replacement and I am very hesitant to do it

Chojun

Turn the key to 'on' and press the auto and off buttons on the climate control at the same time. You should get a flashing '88' - between flashes there might be some segments that stay on, let us know which ones (if any).

nishant11

Thanks a lot.

I tried multiple times but I cannot seem to get into diagnostics mode. I continue to see "Full Auto" on screen. Here is what I did

1.Turn the ignition switch On to run position. Do not touch any buttons on climate control which turning.

2.When in run position, Press the AUTO button and then the OFF button on climate control . Continue to hold both buttons down for 1 minute.

Nothing changes after one minute

Chojun

This assumes you don't have the navigation system. I'm not sure if the steps are the same with navigation. Let us know what you have.

If the system won't display a flashing '88' then you don't have any trouble codes in the climate system.

It sounds like there's an electrical problem, possibly a short or an altogether bad A/C compressor. As a first step I wouldn't assume your ECU is bad.

Iggy

the system was checked for pressure and the pressure sensor is known to be good?

taibud

I have a similar issue, segment G and K light up... any advice on where to start checking... I know nothing about AC

01acls

G, replace the sensor.
K, replace the motor.