Cel On But No Dtc

[HarrierAWD]

Hi

I have a Year 2001 Toyota Harrier (RX300), 1MZ MCU15W Model, 3.0cc AWD,

and 38K miles (60K KM) on it.

Recently CEL ALWAYS comes up after 6-12 minutes short distance drive (Usually

about 6-10 seconds after turned into to highway).

So far no noticeable problem in engine performance. CEL light always off in every restart,

and come back after the 6-12 minutes drives. (Weather condition: 80F/Summer)

Scanned using a OBDIU scanner after ignition is turned on (car is not started), 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 about 6 minute 1st CEL come up.

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

[HarrierAWD]

Confirmed reader problem.

Rescanned and got a P0130 (HO2S Circuit Mulfunction , Bank1 Sensor1).

Any thing to diagnose before replacing the oxygen sensor?