Engine warning light stuck on

[Davearia]

Hi,

My Lexus GS 300 has its engine light stuck on. Was told it might be an issue with fuel I got from Morrisons supermarket. But 2 tanks later it is still on. The only thing that has changed recently is the Battery went flat and I bought a new one from Halfords. The car runs perfectly ok.

Tried this: https://www.lexusofatlanticcity.com/blog/how-do-i-reset-the-maintenance-449910 but no luck.

Thanks,

[IanA2]

10 minutes ago, Davearia said:

Hi,

My Lexus GS 300 has its engine light stuck on. Was told it might be an issue with fuel I got from Morrisons supermarket. But 2 tanks later it is still on. The only thing that has changed recently is the battery went flat and I bought a new one from Halfords. The car runs perfectly ok.

Tried this: https://www.lexusofatlanticcity.com/blog/how-do-i-reset-the-maintenance-449910 but no luck.

Thanks,

Might sound odd, but try cleaning  or replacing your petrol cap......

[mrfunex]

Get an OBD code reader and see what the fault is?

[IanA2]

Tried that in the past, didn't really identify a fault, but new petrol cap worked.

I'm pretty sure Toyota (for it is their cap) know about this.

Only reason I bother with it is for MoT. In fact like the OP, our car runs fine.

[ColinBarber]

There are dozens of reason why the light may be on. Fuel cap is just one, and rarely the issue but if it isn't put on tight then the pressure isn't correct in the tank and you get an error - which will clear after the issue is resolved and you go through three ignition/engine start/stop cycles.

The European series II GS pre-facelift (1998-2000) isn't fully ODBII compliant and many readers won't work. 10/2000-2005 facelift models I believe are ok.

[Davearia]

Hi thanks for you help with this.

I did try asking a mechanic to plug a diagnostic tool in, assuming it was an OBD and he said it didn't seem to work with my 2003 GS 300.

[IanA2]

On 2/9/2019 at 2:19 PM, ColinBarber said:

There are dozens of reason why the light may be on. Fuel cap is just one, and rarely the issue but if it isn't put on tight then the pressure isn't correct in the tank and you get an error - which will clear after the issue is resolved and you go through three ignition/engine start/stop cycles.

The European series II GS pre-facelift (1998-2000) isn't fully ODBII compliant and many readers won't work. 10/2000-2005 facelift models I believe are ok.

As a matter of interest, what sort of fault might there be if the light is on, but the car is running perfectly?

[ColinBarber]

13 hours ago, IanA2 said:

As a matter of interest, what sort of fault might there be if the light is on, but the car is running perfectly?

Typically faults to the O2 sensor heaters, slow reacting O2 sensor, Cat below efficiency threshold, and possibly even misfire errors if it is intermittent. Other issues with O2 sensors or MAF sensors may affect fuel economy but the driver may not notice.

Hard sensor faults will typically put the vehicle into limp mode so you definitely will notice an issue. 

[TigerFish]

Hi thanks for you help with this.
I did try asking a mechanic to plug a diagnostic tool in, assuming it was an OBD and he said it didn't seem to work with my 2003 GS 300.

That is odd, a 2003 car should definitely work.

Where abouts are you located?


Sent from my Iphone using Tapatalk Pro

[m4rkw]

It could be that the OBD pins have been moved out of place so it doesn't make a connection. This happened to me recently, took the car to an auto electrician who popped them all out of the connector and re-seated them and then it was working again.