No Idle-up

**6g4g67** · November 23rd, 2010 06:11 AM

My 230 TE arrived in the philippines with no A/C unit so the its not included in the wiring harness of the ECU. The car Idles at 1500 RPMs and drops to 900-1000 RPM if you put it in Drive or you Turn on the A/C and around 750 if you are in drive and A/C on. It idles lower when in reverse. I found a wiring diagram online and found PIN 19 as the AC comp cntrl. Upon checking my harness blank yung PIN 19. Is it posible or has any body try to connect the AC controler to the ECU? Do you know anybody who can do this kind of job or knows someone who knows to rewire a benz? Or has any body tried to put like a separate idle up for the A/C from another car? I know this is a common problem for servo of the mitsubishis' and one common fix is to put a separate idle up usually from a toyota.

**mbeige** · November 23rd, 2010 02:31 PM

Originally Posted by 6g4g67

My 230 TE arrived in the philippines with no A/C unit so the its not included in the wiring harness of the ECU. The car Idles at 1500 RPMs and drops to 900-1000 RPM if you put it in Drive or you Turn on the A/C and around 750 if you are in drive and A/C on. It idles lower when in reverse. I found a wiring diagram online and found PIN 19 as the AC comp cntrl. Upon checking my harness blank yung PIN 19. Is it posible or has any body try to connect the AC controler to the ECU? Do you know anybody who can do this kind of job or knows someone who knows to rewire a benz? Or has any body tried to put like a separate idle up for the A/C from another car? I know this is a common problem for servo of the mitsubishis' and one common fix is to put a separate idle up usually from a toyota.

You will need somebody who knows his way around the wiring harness of your vehicle. Not sure if it's W123 or W124.

Yes, your ECU will need to be changed to make it think like it has AC. If pin 19 is wired to have the AC function, something else has to tell it when to work and when to shut off. Depending on the year it might also need KLIMA relays. This is a LOT of work.

What's the idle speed when it's in Park, and the engine and AC are running?

Find the FSM (factory service manual) for your car and print out ALL wiring pages related to the AC then compare it to the same diagram for a car originally equipped with AC and give it to your trusted mechanic/electrician to work out the differences and what needs to be done.

**6g4g67** · November 24th, 2010 11:05 AM

W124 po. 1500-1600 rpm in N or P. then around 900-1000 w/AC, then 750 in D and 650 in R.

kailangan siguro rewire ng harness.

AFAIK marami ang mga euro version dito na walang aircon upon arriving here.

I'kk try to ask yung dating mechanic ko na gumawa ng idle up sa dating car ko. baka mas simple yung route na to, parang maglalagay lang ng bypass dun sa intake na tinitrigger nung AC thermostant.