Ls400RR

Purchases my Ls400 a year ago. Drove it right off the lot to the body shop 30 miles away. It drove so nice and smooth. Car was in shop for 3 months getting dolled up. Got the car home and parked it for another 6 months.

Well got to using the car on a daily basis now. Everything was great. Then it all began.

I was almost killed by a T-bone incident. I was making a left turn and the car just fell on its face and turned off. I managed to slip it into neutral and crank it. Then i just dropped it in drive and took off.

Well what I first noticed was that my car on a cold start it would run great as soon as it would warm up my check engine light would come on then the TRAC light and the car would run like crap.
I would have to drop it in "L" then shift my way up to get it moving. If i were in "D" the car would barely move.

Now I did some research and everything pointed to the TPS. Well I spent a whole sunday at the junkyard picking up TPS sensors and other goodies I needed. Got home and Installed of the sensor and it did nothing. I uplugged the battery prior to installation of sensors. It did not work.
I tried adjusting the sensor and nothing.

I possibly did something wrong..

What has me a bit confused is that my LS has TRAC so there are 2 sensors that are right next to each other and look identical. The one I changed to my understanding was


I have three other sensors and they didnt seem to help.

My LS has 180k.

any ideas??

PureDrifter

iTrader: (10)

what code did you get?

Ls400RR

Kinda figured it out today. Well a Lexus specialist told me what exactly it was just by describing the symptoms he even let me borrow his scanner.

My LS is a TRAC and I pulled 26 valve sticking/ 31 maf/vaf/ 52 knock sensor.

But the biggie was a loose wire that was being rubbed by the serpentine belt. Which was the biggest issue that the Lexus specialist told me to look for and he was 100% right.

Gene01

Hi, Ls400RR!
Could I ask where in MD your mechanic is? My daughter-in-law had a terrible experience with the service dept at Towson Lexus and I would really like to help her find an honest and reliable mechanic.
Thanks.

deanshark

Valve sticking???? What do you mean by that?
Which wire are you talking about that was loose? If the Lexus tech told you without even seeing it then it must be common. I'm sure some people would like to know so they could check theirs, if they have the same symptoms.

Ls400RR

TRAC OBDI Diagnostic Codes

11 - Open in TRAC brake main relay circuit

12 - Short in TRAC brake main relay circuit

13 - Open in TRAC throttle relay circuit

14 - Short in TRAC throttle relay circuit

15 - Electric supply to TRAC motor for a long time (fluid leakage)

16 - Open circuit in pressure switch circuit

17 - Pressure switch remains OFF

19 - TRAC motor ON and OFF operation is higher than a predetermined number of times (accumulator pressure leakage)

21 - Open or short in master cylinder cut solenoid valve circuit

22 - Open or short in accumulator cut solenoid valve circuit

23 - Open or short in reservoir cut solenoid valve circuit

24 - Open or short in sub-throttle actuator circuit

25 - Step motor does not move to a position decided by ECU

26 - Sub-throttle valve does not move even when the sub-throttle valve is controlled to fully open position by ECU

27 - When power supply to step motor is stopped, sub-throttle valve does not reach its fully-open position

44 - During TRAC control, NE signals are not input to the ECU

45 - When idle switch is ON, main throttle position sensor signal is 1.5V or higher

46 - Main throttle position sensor signal is 4.3V or higher, or main throttle position sensor signal is 0.2V or lower when idle switch is OFF

47 - When idle switch is ON, sub-throttle position sensor signal is 1.45V or higher

48 - Sub-throttle position sensor signal is 4.3V or higher, or sub-throttle position sensor signal is 0.2V or lower when idle switch is OFF

49 - Open or short in engine communication circuit

51 - Problem in engine control system

52 - Brake fluid level warning switch ON

54 - Open in TRAC motor relay circuit

55 - Short in TRAC motor relay circuit

56 - TRAC pump motor locked

Always ON - Malfunction in ECU


I was gonna take pictures of it but let me see if i can find something relating that wire that rubs the serpentine when it comes loose.

any one have detailed how to's for seafoaming a LS400?
also replacing knock sensor the easy way?

Ls400RR

I believe it was the "CAM SHAFT POSITION SENSOR"

http://www.shastaanesthesia.com/Lexus/Page1.html

deanshark

Ok, I didn't realize the code 26 was for trac b/c you had listed the 31 AFM and 52 Knock sensor in the same sentence so I thought they were all engine codes.
Also, no easy way to change the knock sensor. Might not be the sensor itself, common problem is the knock sensor harness.

Legender

Wow... that's a nice link for TB and water pump replacement...