My engine suddenly died after I turned on my AC. Turned off the AC and started the engine and it did run OK. I've been noticing that whenever I turn on my AC and step on the brakes as I approach a stop, the red battery lights on m my console, should I be worried? I still use my car but not using my AC even in the hot adelaide weather right now. Any advise will be much appreciated.

Yes, you should be worried. A heat wave is coming our way!

What are the engine revs when the battery light comes on? If very low, probably the ISC has failed. You can increase the RPM with the idle air bleed screw on the throttle body, as a temporary fix until you get another ISC.
Alternatively, you could try left foot braking while you keep the rpm up with your right foot, but this takes some practice.

Normal RPM: (Got a TL myself)
Cold start idle: 1500 and up.
Hot idle: 750 rpm.
Hot idle should go UP if you load the engine, turning the steering wheel, AC on, headlights on.

Test your car for RPM and let us know.

My 1997 TE executive had similar problem seven years ago as soon as I picked it up from the car yard, ended up taking it back to them but not being able to fix it till I took it to the local Mitsubishi dealer who said its the stepper motor on the air con so yours might be the same.

My 1997 TE executive had similar problem seven years ago as soon as I picked it up from the car yard, ended up taking it back to them but not being able to fix it till I took it to the local Mitsubishi dealer who said its the stepper motor on the air con so yours might be the same.

Aircon doesn't have a stepper motor. It sends a signal to the ECU when turned on, the ECU then ups the idle via the stepper motor to cope with the extra load. This is commonly referred to as the ISC, or Idle Speed Control, which is on the throttle body.

Yes, you should be worried. A heat wave is coming our way!

What are the engine revs when the battery light comes on? If very low, probably the ISC has failed. You can increase the RPM with the idle air bleed screw on the throttle body, as a temporary fix until you get another ISC.
Alternatively, you could try left foot braking while you keep the rpm up with your right foot, but this takes some practice.

Normal RPM: (Got a TL myself)
Cold start idle: 1500 and up.
Hot idle: 750 rpm.
Hot idle should go UP if you load the engine, turning the steering wheel, AC on, headlights on.

Test your car for RPM and let us know.

Thanks for the reply MadMax. Now I'm really worried. I've been using it since but haven't experienced anything yet (well, I'm not using any AC). I will try to test the engine revs this weekend as you've stated above and will let you know what it is.

Would you have any idea how much would it take to replace this ISC? Can I just go to the wreckers for this?

Many thanks.

ISC from wreckers, yes! Easy job to remove from wrecked car, easy to replace it on your car. (IF that is the problem.)

If the revs turn out to be too low, up the idle with the air bleed screw (anti clockwise), aim for 1,000 - 1,100 rpm in neutral with everything off, should give you a stable idle with A/C on.
Makes the car drivable until you can replace the ISC.

No need to muck around and test various revs etc. Just start the car, warm it up, when you turn the steering wheel there should be a slight increase, turn on the aircon and you should get a quick rev increase then it will settle back down to just above that it was when the aircon was off. If no change in rev or drop in revs then the ISC is kaput

And NO do NOT use the idle bleed screw to UP the revs, this must be done with the MUTTII connected to make sure that base idle is correct, if done like above then this will only serve as a temp solution until the ECU remaps the ICS and will end up where you started

Yes, warm idle, headlights on, crank steering wheel while car is stationary, turn A/C on at the same time. You will soon know if the ISC is working or not. lol (The engine will probably stall)


MUTTII base idle setting and ECU remapping of the ISC only works if the ISC is working, no effect if the ISC has burnt out one of the stepper coils, hence the air bleed screw trick works well. Done it several times on different cars to keep them running.
Good idea to count the number of turns you give it, and set that screw back to where it was when you have a working ISC on there though, and run the engine for a bit to get the ECU to ISC communication back to normal.

Hi there, hope you all had a good break. Been in dark for a while (been busy moving house and taking care of the little ones). I did check this but it seemed to work fine. Revs change when I move the steering wheel or turn the air conditioning on/off. The engine still stops whenever I have my AC turned on and I suddenly step on a break-say approaching a stop light. I've used the car without AC and it works fine and runs well.
Does anyone have a picture on how can I find this ISC? Many thanks to you all.

See grelise's DIY (http://www.aussiemagna.com/forums/showthread.php?t=87966)...

See grelise's DIY (http://www.aussiemagna.com/forums/showthread.php?t=87966)...

Thanks WytWun, I will certainly try this.