NO DTC after Check Engine Light/MIL has illuminated

Hi

Year 2001 Toyota Harrier (Lexus RX300), 1MZ MCU15W Model, 3.0cc AWD,
and 38K miles (60K KM) on it.
Recently Check Engine Light/CEL ALWAYS comes up after abt 1 mile or 6-12 minutes short distance drive CEL light always off in every restart,
and come back after the 6-12 minutes drives. (Weather condition: 80F/Summer)

Scanned using a OBDII scanner after ignition is turned on (car is not started), and
CEL is off.
DTC: 00 (none)

Scanned using a OBDII scanner after the CEL is turned on (after car ran for 6-12 minutes):
DTC:00 (None)

I/M Status:
MIL : ON
MISFIRE: NOT READY
FUEL: N/A
CCM : READY
CAT : READY
HCM : N/A
EVAP: READY
2AIR: NOT READY
A/C: N/A
O2S: READY
HO2S: N/A
EGR: READY

Other info that I am not sure it help: 1 hour before the 1st CEL is on, I did an emergency brake to avoid hitting the front car. No damage done and no CEL on. Parked and off the car for 1 hour, after drove about 6 minute 1st CEL come up.

Any hints/helps is much appreciated. Thanking you in advance.