Mechanics

LEXUS GX 470 SENSOR PROBLEM

2003 Lexus GX 470 • 114,504 miles

I have lexus gx 470 2003 model my check engine light came on with vsc, vsc trac came on to I used the scan tools to clear the fault I have cleared the fault I drove the lexus for 1 week everything is going good but when I drove on the highway after 15km the light came up again what should I do to fix it and I have other problems when I park the lexus in the nigth the next day morning the back suspension is down so when I start the lexus it will go up but not always it will do like that how can I fix it to
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Mohmed
December 9, 2012.



Erasing codes fixes nothing. The problem needs to be identified, diaged, repaired.

What were/are the codes?

Roy

The code is p0031 oyxgen sensor heater control ciruit low bank1 sensor 1 and about the back suspension there is no code how can I fix it

Tiny
Mohmed
Dec 9, 2012.
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used. But for the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.

The heated oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. This is used to detect the oxygen concentration in the exhaust gas and provide the ECM with feedback control the air-fuel ratio.

When the air-fuel ratio becomes LEAN, the oxygen concentration in the exhaust gas increases. And the heated oxygen sensor informs the ECM of the LEAN condition (small electromotive force; 0.45 V ). The ECM judges by the electromotive force from the heated oxygen sensor whether the air-fuel ratio is RICH or LEAN and controls the injection time accordingly. However, if the malfunction of the heated oxygen sensor causes an output of abnormal electromotive force, the ECM becomes unable to perform the accurate air-fuel ratio control.

The heated oxygen sensors include a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), current flows to the heater in order to heat the sensor for the accurate oxygen concentration detection.

HINT: The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the B+ side of the circuit.

HINT: Bank 1 refers to the bank that includes cylinder No.1.
Bank 2 refers to the bank that does not include cylinder No.1.
Sensor 1 refers to the sensor closest to the engine body.
Sensor 2 refers to the sensor farthest away from the engine body.

Wiring Diagram

Step 1 - 2

Step 3

Step 4

INSPECTION PROCEDURE

HINT: If different DTCs that are related to different system are output simultaneously while terminal E2 is used as a ground terminal, terminal E2 may be open.
Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data re cords the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. At the time of the malfunction.

I want to know should I change the p0031 oyxgen sensor heater control ciruit low bank 1 sensor 1 or not

Tiny
Mohmed
Dec 9, 2012.
I sent you the chart for checking the code.

I dont know any of the readings. A code never identifies a bad part, just a failed system. Hate to see you waste money on a sensor that may not be bad.

Roy

Let me tell you what is happing when I drive the lexus with normal speed in local road even for weeks not on highway everything will me fine and the check engine light with vsc, vsc trac will not come on, but when I go to the highway and run with speed after 10km the check engine light with the vsc, vsc trac will come on I put the scan and I check the fault p0031 oyxgen sensor heater control ciruit low bank 1 sensor 1 so what is the solution

Tiny
Mohmed
Dec 10, 2012.
What do u mean by faild system explain

Tiny
Mohmed
Dec 10, 2012.