Clearing Codes?
 

Is there a way to clear the codes. I just replaced O2 sensors but light still stay on.

disconnecting the battery or pulling the fuse for a few moments usually does the trick. never tried on lexus.

clearing codes
 

pull the EFI fuse. It's in the fuse block under the hood.

Tried the battery disconnect - didn't work. Tried the fuse and lights went out until I restarted the car and they came back on.

Take the EFI fuse (30A) from the under hood fuse box out more than 10 seconds, with the ignition off.

I took fuse out for half an hour - it didn't help.

codes
 

There's a black rectangular plastic box with a flippy lid on it at the battery side of the engine. If you look at the inside lid, there's a litlle map of the terminals inside. Take a jumper wire and connect terminals TE1 and E1. Go look at the combination meter and read your code with the key ON. Count the flashes from the check engine light. It'll be a two digit code like 25, 51, etc. That connection also allows you to read static ignition timing, but the V8 isn't adjustable. You can also check all codes (abs, trac, srs) by jumping Tc to E1 at the OBD1 connector under the dash.

You still have a code. It resets when you're turning the car on. Something's probably unplugged.

Re: codes
 

Possible... Check every vacunm lines, especially the line from the intake hose that connect the MAF sensor to the plenum.

SC300 ?Check for code?
 

Fire,
Can I check the code for the SC300 that way also:

There's a black rectangular plastic box with a flippy lid on it at the battery side of the engine. If you look at the inside lid, there's a litlle map of the terminals inside. Take a jumper wire and connect terminals TE1 and E1. Go look at the combination meter and read your code with the key ON. Count the flashes from the check engine light. It'll be a two digit code like 25, 51, etc. That connection also allows you to read static ignition timing, but the V8 isn't adjustable. You can also check all codes (abs, trac, srs) by jumping Tc to E1 at the OBD1 connector under the dash.

Thanks, Howard

By the way, I get a transient engine light sometimes when i'm at a stop and when the rpms are just below 1000? Guess I have to wait til it stays on to diagnose? but i don't want to be stuck on the side of the road at that point? any help?

Stupid question but what is a combination meter and where do I connect it. All vacuum hoses are connected.

Clearing Codes?
 

Any OBD1 Lexus or Toyota code is read that way, so yeah, it works on all SC's till '95 or so.

Combination meter is where the check engine light is.

Make a jumper wire to connect terminals TE1 and E1 under the hood or Tc and E1 under the dash.

BTW...the check engine light will always be on when the ignition is on, but the engine is not running.

Jumped TE1 and E1 under hood. Code comes up at 29. What does this mean?

Codes
 

There is no code 29. Here are the meaning of the codes:

1 Normal Condition.
2 Air Flow Meter signal.
3 Ignition signal.
4 Engine Coolant Temperature Sensor signal.
5 Oxygen Sensor.
6 RPM signal (Crank Angle Pulse).
7 Throttle Position Sensor signal.
8 Intake Air Temperature Sensor signal.
9 Vehicle Speed Sensor signal.
10 Starter signal.
11 Switch signal.
11 ECU/ECM.
12 Knock Control Sensor signal.
12 RPM signal.
13 Knock Control CPU (ECM).
13 RPM signal.
14 Turbocharger Pressure.
14 Ignition signal.
21 Oxygen Sensor.
22 Engine Coolant Temperature Sensor signal.
23 Intake Air Temperature Sensor signal.
24 Intake Air Temperature Sensor signal.
25 Air-Fuel Ratio Lean.
26 Air-Fuel Ratio Rich.
27 Sub Oxygen Sensor signal.
28 No. 2 Oxygen Sensor signal.
31 Air Flow Meter signal (Vacuum Sensor signal).
32 Air Flow Meter signal.
34 Turbocharger Pressure signal.
35 Turbocharger Pressure Sensor signal.
35 HAC Sensor signal.
41 Throttle Position Sensor signal.
42 Vehicle Speed Sensor signal.
43 Starter signal.
51 Switch signal.
52 Knock Sensor signal.
53 Knock Sensor signal.
54 Inter-cooler ECM signal.
71 EGR System.
72 Fuel Cut Solenoid signal.
78 Fuel Pump Control signal.
81 TCM Communication.
83 TCM Communication.
84 TCM Communication.
85 TCM Communication.
:) :(

No 29? Engine light flashes twice then pause then nine times.

TRIED THE TEST
 

When I tried the diagnostic test with the thing under the hood, and I looked at the check engine light it was blinking with the Over Drive light. They never stopped. I wanted to know what that means. When I did the diagnostic test with the thing under the dash the check engine light just stayed on.