code P702

jgananE320 · 11-02-2009, 09:53 PM

My 2002 E320 is having problems with the tranny. the code read P702 transmission controll electrical system. i read that i should check ecu connections for fluid. can someone tell me the exact location of the tanny ecu? is it on the side of the engine block or the engine compartment? drivers or passenger? i really need a diagram or something. im a do it youselfer but i dont know where to start and i really dont want to bring it to the stealership.

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99210 · 11-03-2009, 01:06 PM

trans ecu is in the engine compartment on passanger side near fire wall in contorl unit box //cover has about 4 or5 screws holding it on//remove cover trans ecu has two connectors, both are same size, rectangular is shape//

jgananE320 · 11-03-2009, 01:18 PM

thanks 99210. ill look for it when i get off of work. i'll give u an update on what i find. should i disconnect the bat to clear the code from limp mode?

jgananE320 · 11-04-2009, 10:42 AM

ok i disconnected the battery i hopes that this would clear the code. while the bat was disconnected i checked the ecu/egs under the hood and it was dry as a desert. i also got under and checked the round plug near the trans pan. trans pan was completely dry and when i took the round plug out the was about two drips of fluid that came out. i cleaned it out with MAF cleaner and let it dry before putting it back in. when i connected the bat back i noticed the abs and the BAS light stayed on when i started the car. i also need to put in code for radio. when i started the car, it was still in limp mode. i shut it off and tried to start again...THIS TIME IT WONT TURN OVER. it tries to for a quarter of a sec then gives up. i turned on the headlights then tried to turn it over and it worked!!!! IHAVE TO TURN ON THE HEADLIGHTS IN ODER TO START THE CAR!!! WTF!!! IS THIS A RELATED PROBLEM OR A NEW ONE? I called a local independant shop, they use a SnapOn scanner(guy on the phone didnt know what limp mode was at first til i explained it), will this work to reset the limp mode or should i find a shop with a Star scanner. Does anyone know a good Indy here in san diego? i need to find one. Should i go to the Stealership or continue DIY? Sorry for all the Q's, im desperate! Oh Lord please help!

TMAllison · 11-05-2009, 01:41 AM

Dont know if Snapon will clear it or not. Indy who cant understand that question on the phone=shop elsewhere.

Fix problem/dont erase code=LHM.

Sometimes dealer=lesser of evils.

jgananE320 · 11-05-2009, 11:55 AM

ok i brought it to MB of Escondido. they gave me a free loaner(i had to pay $15 for gas charge) til i get my car back. i'll cross my fingers and see how it goes.

jgananE320 · 11-05-2009, 05:00 PM

ok... so dealer calls back and says "Bad Battery"!!! their scanners stated low voltage to the tcu and other sensors. they also gave me a list of other unrelated things like the tranny mounts leaking. anyone have a DIY on that? i'm sure i can tackle this one my self. i'd be saving $752.60 if i do.

TMAllison · 11-05-2009, 07:41 PM

Pretty painless.

There is a trans mount DIY on peachparts.com Is fairly easy.

11-04-2009, 10:42 AM	#4
jgananE320 Junior Member Join Date: Jan 2009 Location: Diego, So Cal Posts: 23 Drives: 2002 E320	ok i disconnected the battery i hopes that this would clear the code. while the bat was disconnected i checked the ecu/egs under the hood and it was dry as a desert. i also got under and checked the round plug near the trans pan. trans pan was completely dry and when i took the round plug out the was about two drips of fluid that came out. i cleaned it out with MAF cleaner and let it dry before putting it back in. when i connected the bat back i noticed the abs and the BAS light stayed on when i started the car. i also need to put in code for radio. when i started the car, it was still in limp mode. i shut it off and tried to start again...THIS TIME IT WONT TURN OVER. it tries to for a quarter of a sec then gives up. i turned on the headlights then tried to turn it over and it worked!!!! IHAVE TO TURN ON THE HEADLIGHTS IN ODER TO START THE CAR!!! WTF!!! IS THIS A RELATED PROBLEM OR A NEW ONE? I called a local independant shop, they use a SnapOn scanner(guy on the phone didnt know what limp mode was at first til i explained it), will this work to reset the limp mode or should i find a shop with a Star scanner. Does anyone know a good Indy here in san diego? i need to find one. Should i go to the Stealership or continue DIY? Sorry for all the Q's, im desperate! Oh Lord please help! Last edited by jgananE320; 11-04-2009 at 10:52 AM. Reason: accidentally hit enter

11-05-2009, 01:41 AM	#5
TMAllison Super Member Join Date: Jun 2008 Location: Bay Area, CA Posts: 680 Drives: 99' E300	Dont know if Snapon will clear it or not. Indy who cant understand that question on the phone=shop elsewhere. Fix problem/dont erase code=LHM. Sometimes dealer=lesser of evils. __________________ T. Allison 85' 300D 311k miles 99' E300 275k miles

11-05-2009, 07:41 PM	#8
TMAllison Super Member Join Date: Jun 2008 Location: Bay Area, CA Posts: 680 Drives: 99' E300	Pretty painless. There is a trans mount DIY on peachparts.com Is fairly easy. __________________ T. Allison 85' 300D 311k miles 99' E300 275k miles

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11-03-2009, 01:06 PM	#2
99210 Junior Member Join Date: Nov 2009 Posts: 30 Drives: 1999 e320	trans ecu is in the engine compartment on passanger side near fire wall in contorl unit box //cover has about 4 or5 screws holding it on//remove cover trans ecu has two connectors, both are same size, rectangular is shape//

11-03-2009, 01:18 PM	#3
jgananE320 Junior Member Join Date: Jan 2009 Location: Diego, So Cal Posts: 23 Drives: 2002 E320	thanks 99210. ill look for it when i get off of work. i'll give u an update on what i find. should i disconnect the bat to clear the code from limp mode?

11-05-2009, 11:55 AM	#6
jgananE320 Junior Member Join Date: Jan 2009 Location: Diego, So Cal Posts: 23 Drives: 2002 E320	ok i brought it to MB of Escondido. they gave me a free loaner(i had to pay $15 for gas charge) til i get my car back. i'll cross my fingers and see how it goes.

11-05-2009, 05:00 PM	#7
jgananE320 Junior Member Join Date: Jan 2009 Location: Diego, So Cal Posts: 23 Drives: 2002 E320	ok... so dealer calls back and says "Bad Battery"!!! their scanners stated low voltage to the tcu and other sensors. they also gave me a list of other unrelated things like the tranny mounts leaking. anyone have a DIY on that? i'm sure i can tackle this one my self. i'd be saving $752.60 if i do.

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