Code 19 And An Old 'wwest' Message

[CanadaCraig]

Hi Guys!! :)

I've been searching and reading a lot of old LOC messages. One that caught my eye was one posted by 'wwest'. [Hi 'wwest' - hope you don't mind me doing this] Last fall - my 1993 LS400's 'TRAC' light came on and stayed on. [usually after being driven for about 15 minutes or so] The dealer simply cleared the memory of the code and told me to come back IF the TRAC light comes on again. It hasn't - so far.

The following was posted by 'wwest' on December 6th, 2004.

What the diagnostic [code 19] really means is that the Trac brake fluid pressure replenishing pump is running too often. Each time you apply the brakes the Trac ecu checks the brake fluid backup pressure at the accumulator. If the Trac pump has to restart to replenish the pressure fluid pressure on ten sequential brake applications the diagnostic indication will be illuminated.

Oftentimes you can just sit in your driveway and count as you apply the brakes and on the tenth one the light will come on.

That can be because the accumulator has lost it 3000PSI of nitrogen charge or it could also mean that some small debris is blocking one of the reverse flow check valves open.

A complete brake fluid flush fixed mine. If you take it to Lexus to have this done be sure and point out the extra bleed valves, Lexus of Seattle didn't know of them until I pointed them out.

I tried pumping the brakes 10 times - in fact - 50 times - but the TRAC light didn't come on. Not sure if that proves [or disproves] anything.

Here are a few questions. If you - 'wwest' would take the time to answer [or anyone else with answers] it would be greatly appreciated.

WHAT IF the TRAC accumulator pump only needs 9 times to build up pressure - would that keep the TRAC light from coming on?! [and creating a 'code 19' fault]

Does the number of times needed to build up pressure have to be within a certain time frame [in order to trigger a 'code 19'] or does the ecu remember each time and even if it took 5 hours to reach 10 times - THAT would trigger a 'code 19'. [does that makes sense?]

WHAT IF the TRAC accumulator pump continuously has to build up pressure - over and over again [but never enough times to trigger the TRAC light] as you're driving - would THAT have ANY effect on the performance of the car? In other words - would the car FEEL as though it was 'braking' even if you are accelerating? [each time a pump was working]

Thank you very much.

Craig!! :)

[CanadaCraig]

HELLO?

ANYBODY THERE?!

:cries:

[wwest]

Well, yes, on my way back home from the 24 hours of daytona and didn't take the laptop.

Each time you apply the brake the Trac ECU checks the accummulator pressure level and if it is low it restarts the pump. Absent actual useage the pressure should never leak down except for maybe long periods in the garage.

If the pump must be restarted ten time sequentially then you have a pressure leak within the system and the diagnostic comes on.

It might be a good idea to have the brake system flushed and refilled and be sure the bleed valves on the accummulator pump and ABS pump are bled/opened. That was what cured my Trac problem.

[CanadaCraig]

Hi wwest!! :)

Thank you. I appreciate the response.

AND I'll do [or have done] exactly what you suggest.

IF the accumulator and/or ABS pumps have NEVER been bled/opened - that would have to cause SOME problems. [i would think]

Thanks,

Craig!! :)

[wwest]

Hi wwest!! :)

Thank you. I appreciate the response.

AND I'll do [or have done] exactly what you suggest.

IF the accumulator and/or ABS pumps have NEVER been bled/opened - that would have to cause SOME problems. [i would think]

Thanks,

Craig!! :)

Well.......??

[Alexander the o.k.]

Bump.

For those with trac light issues.

Any follow up?

Great post WWEST.

[UCF3]

Bump.

For those with trac light issues.

Any follow up?

Great post WWEST.

have you read the code yet?

[Alexander the o.k.]

Cleared old codes. Nothing new yet.

I do have an ac code 13 tho.

[jcrome04]

Off topic but....

Hey Craig I see you're up in Victoria! I'm just across the water here in Port Angeles! You ever make it to this side of the water? Do you know SRK?