Need help - LS400 1990 - gearbox problems when lights are turned on
#1
Driver School Candidate
Thread Starter
Need help - LS400 1990 - gearbox problems when lights are turned on
Hi everyone,
I have a problem with my LS400, make 1990.
During the driving, when I turn the car lights on - gearbox goes to some kind emergency mode. Car drive on one gear (gearbox doesn't change gears), and on the display there are lighting controls: "Gearbox R" and "Rear Antifog Lights". Of course, also lights D (as this mode is selected), and antifog lights are turned off.
When I turn the car lights off - everything goes to normal. Transmission works fine and changes gears normally.
I checked:
- battery disconnecting. Problems disappear, but only for a moment
- voltage charging: 13,88V without load, 12,39V with turned lights, A/C, seat heating and radio
- transmission oil level - ok
- fuses next to battery - all are ok
I haven't checked yet error codes.
I have a problem with my LS400, make 1990.
During the driving, when I turn the car lights on - gearbox goes to some kind emergency mode. Car drive on one gear (gearbox doesn't change gears), and on the display there are lighting controls: "Gearbox R" and "Rear Antifog Lights". Of course, also lights D (as this mode is selected), and antifog lights are turned off.
When I turn the car lights off - everything goes to normal. Transmission works fine and changes gears normally.
I checked:
- battery disconnecting. Problems disappear, but only for a moment
- voltage charging: 13,88V without load, 12,39V with turned lights, A/C, seat heating and radio
- transmission oil level - ok
- fuses next to battery - all are ok
I haven't checked yet error codes.
#3
Driver School Candidate
Thread Starter
Thank you for reply. You mean rear trunk, as showed below?
I have checked errors today. There is one engine faulty: Code 21 Oxygen sensor signal or heater malfunction (on left bank). For me it seems not to be relevant to transmission problems. Am I right?
There isn't any transmission errors.
When engine is cold, the malfunction doesn't exist. After warm up (driving about 6-7 miles) showed up again. But it disappear when I turned lights off.
Maybe important fact - Lexus has new parts:
- distributor cap (original Toyota)
- distributor cam
- ignition wires (original Toyota)
- spark plugs
- timing belt (original Toyota)
- tensioner pulley
- idler pulley
- hydraulic damper
Installed by professional mechanics (I hope) about 60 miles ago.
I have checked errors today. There is one engine faulty: Code 21 Oxygen sensor signal or heater malfunction (on left bank). For me it seems not to be relevant to transmission problems. Am I right?
There isn't any transmission errors.
When engine is cold, the malfunction doesn't exist. After warm up (driving about 6-7 miles) showed up again. But it disappear when I turned lights off.
Maybe important fact - Lexus has new parts:
- distributor cap (original Toyota)
- distributor cam
- ignition wires (original Toyota)
- spark plugs
- timing belt (original Toyota)
- tensioner pulley
- idler pulley
- hydraulic damper
Installed by professional mechanics (I hope) about 60 miles ago.
Last edited by pilot84; 01-29-17 at 10:01 AM.
#4
Lead Lap
Yes, the driver side trunk hinge. It may sound strange but the transmission can act up and the reverse indicator in the cluster light up when one or more of these wires break. It happened on the 1990 LS400 I used to have in around 2003.
There are threads about this problem that you can probably find by searching for the word "hinge" in the LS400 forum.
There are threads about this problem that you can probably find by searching for the word "hinge" in the LS400 forum.
The following users liked this post:
pilot84 (01-30-17)
#5
When you open the trunk you will see a plastic cover of sorts on that hinge bar, remove it, you shouldn't even need any tools to do it just pull from under in the front kinda.
The wires are under that cover.
The wires are under that cover.
The following users liked this post:
pilot84 (01-30-17)
The following users liked this post:
pilot84 (01-30-17)
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