Ls430 2002 How To Read Fault Codes

[maniek_ls400]

Hi All !

I just bought LS430 2002 with check engine ON. At dealer checked on diagnostic tester three codes P0171, P0325 and P0420. Car slowly reacts on pedal depress, accelerates from 1000-2400 then PRM increased slowly to 4000 and then 'new knock' and power back. After some kilometers there is smell and filling hot under floor.

I checked codes and know what its means - my first idea is to replace catalytic converter on right side ? What is your opinion ?

When I reset ECU then car accelerates better (not as expected compared to own LS400), but after some time (0.5hr. of driving) check engine is back.

I'd like to check DTC codes by my self with no dealer labour - is it possible to use OBD socket and do some shorts (in camry and old LS'92 it was T0 end E1) ?

Thank you for advice (I'll not sell LS430 ;) )

Regards,

Mariusz

LS430 2002

LS400 1999 (for sale)

LS400 1992 (sold)

[Mybikesacx500]

What do the codes mean? Let us know and you might get more theories back. A hot cat can mean it is getting unburnt fuel, maybe ignition issues.

I had a bad HT coil that resulted in very low power and both cats getting red hot

Only Gold members are supposed to offer cars for sale, but since you have mentioned it, perhaps PM me or get me on ian.shearer6@gmail.com......

[Mybikesacx500]

[Looked up the codes out of idle curiosity, If it was me, I'd be checking the knock sensor and wiring, maybe swap them across the banks, see if the codes change

A code P0420 may mean that one or more of the following has happened:

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Retarded spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings
• A code P0171 may mean that one or more of the following has happened:
  • The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
  • There could be a vacuum leak downstream of the MAF sensor.
  • A code P0325 most likely means one or more of the following has happened:
    • The knock sensor is faulty and needs to be replaced
    • There is a wiring short/fault in the knock sensor circuit

[Mybikesacx500]

To answer the question you asked, I don't think there is a way to read OBD2 codes other than with a reader, eBay has some pretty neat ones that link to a laptop USB port, but I am a computer nut, perhaps that doesn't appeal to everyone. The codes I found on the internet are generic ones, I don't know if Lexus have modified their system or not.

feel free to get in touch with details of the green '99

[John N]

I can't remember where I found the following information about reading the fault codes on the LS430, but it looked interesting so I copied it and filed it away.

Give it a try and see if it works.

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"To access the Diagnostic Menu on the touch screen do the following".

1. Gear selector in park.

2. Handbrake on.

3. Ignition to ACC, (or start the engine if you want to do a speed check etc) wait for navi screen to power up, click "I Agree" (or buy the Vias Ipod or dvd lead and it does it for you)

4. Press and HOLD the OPTION button and AT THE SAME TIME...

5. Turn headlights from off to sidelights five times i.e. off/side/off/side/off.

6. To exit the menu, turn off the ignition, car will then behave as normal.

You will then get a screen displayed, it shows if there are any faults stored in the ECU, you must wait until it populates the empty spaces.

I got this from Club lexus forums from a Lexusthai he shows pictures of all the screens you will see, but I repeat, you must wait until it populates the empty

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John N

[maniek_ls400]

John N

John,

many thanks for information - believe me - I found the same today via goggle search :-)

Two days ago I bought OBD2 <-> USB interface for 10 EU and read codes, but tomorrow will check procedure provided by you.

Last update about my LS430:

- replaced catalytic converters (both) - errors disappears and car (after EFI reset) was better till P0325 appears again and 'lex' doesn't accelerate at all.

I ordered (used part) of knock sensor - waiting for delivery - during this week will do a change (I know how deep I need to go - two years ago I repaired starter by my self on LS400). I'll make pictures and put on my picassa site.

Regards,

Mariusz