LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

have to replace shift lock control ECU?

Thread Tools
 
Search this Thread
 
Old 04-16-09, 07:21 PM
  #1  
qha_vn
Pole Position
Thread Starter
 
qha_vn's Avatar
 
Join Date: Nov 2007
Location: VN
Posts: 324
Likes: 0
Received 0 Likes on 0 Posts
Default have to replace shift lock control ECU?

I could not move shifter out of P without pressing shiftlock override

key lock still works fine (cant turn off if not P)

shiftlock solenoid resistance is in spec: 25 ohm, still operate with direct voltage. voltage out from shiftlock control ECU to solenoid when depressing brake is 7.9-8.5 volts (still good according to repair manual)

it seems that the current isnt enough as I connect a 1 watt lamp to the solenoid wire and its not lit up

what might be the cause, can it be repaired or need replacement?

ls400 1990 120k
Old 04-16-09, 07:30 PM
  #2  
Kansas
Lead Lap
 
Kansas's Avatar
 
Join Date: Jan 2004
Location: Kansas
Posts: 3,585
Received 252 Likes on 199 Posts
Default

The most common cause of your problem is a bad brake light switch at the top of the brake pedal lever up under the dash. Do your brake lights work when you can't shift out of Park?
Old 04-16-09, 08:18 PM
  #3  
qha_vn
Pole Position
Thread Starter
 
qha_vn's Avatar
 
Join Date: Nov 2007
Location: VN
Posts: 324
Likes: 0
Received 0 Likes on 0 Posts
Default

am sorry not to mention, the brake light is still on. thats why I have ~8 volts at solenoid wires when depressing brake
Old 04-18-09, 11:26 PM
  #4  
qha_vn
Pole Position
Thread Starter
 
qha_vn's Avatar
 
Join Date: Nov 2007
Location: VN
Posts: 324
Likes: 0
Received 0 Likes on 0 Posts
Default

i found the problem, its the shiftlock control ECU, I have rewired to by pass the ECU by connecting the solenoid with stop light wire and P1 wire of shift lock switch.

fyi, from shiftlock switch out, there are 3 wires, the middle one is connected to mass via shiftlock control ECU, the other 2 are P1 and P2. When shift lever is in P position. P1 and P will be connected (to mass). in other positions other than P, P2 and P are connected. by connecting solenoid (2 wires) to stop light (+) and P1 (-), the solenoid will be energized only when shifter in P and brake pedal depressed, providing similar function of the ECU

its better to have a relay in the middle, but given the solenoid looks quite small, current flow thru it would be small, also the time when we hit brake pedal to moving shifter off P is fast. I connected solenoid directly for simplicity.

work like OEM now without any $

I took some pix as well for the by pass setup, will post it later
Old 04-21-09, 03:48 AM
  #5  
qha_vn
Pole Position
Thread Starter
 
qha_vn's Avatar
 
Join Date: Nov 2007
Location: VN
Posts: 324
Likes: 0
Received 0 Likes on 0 Posts
Default

here we go

This wire (+12v) is from stop light. its on when brake pedal depressed



this wire provide mass when shift lever in P. its actually connected to the middle wire in P, disconnected when not in P



I connected those 2 to the solenoid. completed wiring



the faulty shiftlock control ECU



its that simple. work very well
Old 01-28-20, 08:06 PM
  #6  
Ham
Pit Crew
 
Ham's Avatar
 
Join Date: Dec 2018
Location: Delaware
Posts: 180
Received 1 Like on 1 Post
Default

Originally Posted by qha_vn
here we go

This wire (+12v) is from stop light. its on when brake pedal depressed



this wire provide mass when shift lever in P. its actually connected to the middle wire in P, disconnected when not in P



I connected those 2 to the solenoid. completed wiring



the faulty shiftlock control ECU



its that simple. work very well
I know this is old but mine just stopped working. Where did you tap into the Brake light wire at?
Old 10-26-20, 03:59 PM
  #7  
Barrymic
Driver School Candidate
 
Barrymic's Avatar
 
Join Date: Oct 2020
Location: Georgia
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default Where is the shift lock ecu located on a 2007 Lexus is250

The Lexus dealership is saying the shift lock ecu is bad. $800 fix.
does anyone know where this part is located? I will replace it myself if I can find it.
Old 10-26-20, 09:31 PM
  #8  
sdls
Lexus Champion
 
sdls's Avatar
 
Join Date: Sep 2010
Location: NA
Posts: 2,218
Received 293 Likes on 241 Posts
Default

Originally Posted by Barrymic
The Lexus dealership is saying the shift lock ecu is bad. $800 fix.
does anyone know where this part is located? I will replace it myself if I can find it.
the people in the 2007 is250 forum might know
Old 10-26-20, 09:40 PM
  #9  
Amskeptic
Intermediate
 
Amskeptic's Avatar
 
Join Date: Jul 2009
Location: NY
Posts: 444
Received 88 Likes on 61 Posts
Default

Originally Posted by Barrymic
The Lexus dealership is saying the shift lock ecu is bad. $800 fix.
does anyone know where this part is located? I will replace it myself if I can find it.

Shift lock ecu is located under the center console just behind the shifter.
Sez my manual.
Colin
(p.s. I would happily tear into my old ecu and check all the solder connections before coughing up so much money for a new one. Then I'd put out a call for a used one on the national used car parts network.)
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
rhwimmers
GS - 3rd Gen (2006-2011)
6
09-19-14 10:46 PM
shabbyblue
GS - 2nd Gen (1998-2005)
1
04-30-13 10:40 PM
lynnjer
RX - 1st Gen (1999-2003)
1
03-05-06 12:29 PM
dj.ctwatt
LS - 1st and 2nd Gen (1990-2000)
2
12-22-03 09:35 PM



Quick Reply: have to replace shift lock control ECU?



All times are GMT -7. The time now is 06:49 AM.