is this normal?
s:D :D s:D
No, did you plug your O2 sensors back in?
Cheeck all your connections, then remove the ECU fuses for half an hour to reset the light. If it comes back, you'll need to read the code to narrow the fault down.
I will give that a go, the O2 sensors went back in unharmed and happy?
fingers crossed
thanks again
DB
yea I'm worried about a light too. I'm going to do this but I don't want a light on all the time throwing the car out of whack.
It may be that the main cat isn't cleaning up the engine output enough to ensure the emissions are 'clean' - you'll get a check engine light then too. How many miles has your Roadster done?
On a more practical note though, its probably worth checking all the connectors for the O2 sensors are pushed home fully.
are all of the o2 sensors not before the main cat anyway? or is there a third after the cat?
Quote from: "Richie"are all of the o2 sensors not before the main cat anyway? or is there a third after the cat?
On UK, Euro & US cars there's a third O2 sensor after the main CAT, which is used to monitor the 'health' of the CAT. If the CAT stops working efficiently, the ECU will flag up a CEL (in some areas, notably California, such a CEL means you'll fail a smog check. In the UK, we just go on measured emissions, IIRC - don't think a CEL will fail an MOT).
well might CEL is on and Mr. T said it was the 3rd O2 sensor so I was going to get that replced but would that mean that maybe the main cat is going bad, or would that throw up a different code?
Quote from: "mefarri"well might CEL is on and Mr. T said it was the 3rd O2 sensor so I was going to get that replced but would that mean that maybe the main cat is going bad, or would that throw up a different code?
I believe - but don't quote me, as I haven't checked the code list s:) :) s:) - that there are two codes - one for 'sensor failure' and the other for 'signal out of spec' - the latter would indicate the cat, the former the sensor.
that's what I was thinking.
Quote from: "aaronjb"IIRC - don't think a CEL will fail an MOT).
By itself, I think you're right, but if the CEL is caused by the emissions being out of line, I guess there's a chance you'll fail the MOT emissions check.
Quote from: "phil4"Quote from: "aaronjb"IIRC - don't think a CEL will fail an MOT).
By itself, I think you're right, but if the CEL is caused by the emissions being out of line, I guess there's a chance you'll fail the MOT emissions check.
I believe this is right Phil and the third sensor is not just a static level monitor but also controls the levels going into the cat. Anyone to confirm s:?: :?: s:?:
Quote from: "heathstimpson"Quote from: "phil4"Quote from: "aaronjb"IIRC - don't think a CEL will fail an MOT).
By itself, I think you're right, but if the CEL is caused by the emissions being out of line, I guess there's a chance you'll fail the MOT emissions check.
I believe this is right Phil and the third sensor is not just a static level monitor but also controls the levels going into the cat. Anyone to confirm s:?: :?: s:?:
Third sensor has no control functions at all. It is simply used by the ECU to monitor the performance of the cat. It does this by comparing the signal from the 3rd O2 with that of one of the primary O2 sensors in the manifold. If you were to hook an oscilloscope up to the sensors in the manifold, you'd see that the O2 content isnt in fact stable, it oscillates around the "ideal" point, going high, then low, then high again, forming a square wave. The actions of the catalysts will even this oscillation out, giving a far steadier signal at the 3rd O2 Sensor
IF they are working properly. If the cats are dead (or missing) and are having no effect, then the signal at the 3rd O2 will match the one at the primary O2 sensors in the manifold.
This matching signal is then recognised as a fault, and the Check Engine Light (CEL) is lit, and a code stored in the ECU memory. Thats as far as it goes though, unlike a failure of a primary O2 sensor, which causes the engine to revert to a "safe" open loop mode of operation, a 3rd O2 sensor failure is not safety or operation critical, and thus the engine management remains in its normal mode, and the defect has no effect on performance.
However, last time I checked, a lit Check Engine Light, or one that fails to light and go out when starting the engine, is an MOT failure.
Cheers for that Grant; I knew you would know s:wink: :wink: s:wink: How do you have so much knowledge on these things s:?: :?: s:?:
Quote from: "GSB"Quote from: "heathstimpson"Quote from: "phil4"Quote from: "aaronjb"IIRC - don't think a CEL will fail an MOT).
By itself, I think you're right, but if the CEL is caused by the emissions being out of line, I guess there's a chance you'll fail the MOT emissions check.
I believe this is right Phil and the third sensor is not just a static level monitor but also controls the levels going into the cat. Anyone to confirm s:?: :?: s:?:
Third sensor has no control functions at all. It is simply used by the ECU to monitor the performance of the cat. It does this by comparing the signal from the 3rd O2 with that of one of the primary O2 sensors in the manifold. If you were to hook an oscilloscope up to the sensors in the manifold, you'd see that the O2 content isnt in fact stable, it oscillates around the "ideal" point, going high, then low, then high again, forming a square wave. The actions of the catalysts will even this oscillation out, giving a far steadier signal at the 3rd O2 Sensor IF they are working properly. If the cats are dead (or missing) and are having no effect, then the signal at the 3rd O2 will match the one at the primary O2 sensors in the manifold.
This matching signal is then recognised as a fault, and the Check Engine Light (CEL) is lit, and a code stored in the ECU memory. Thats as far as it goes though, unlike a failure of a primary O2 sensor, which causes the engine to revert to a "safe" open loop mode of operation, a 3rd O2 sensor failure is not safety or operation critical, and thus the engine management remains in its normal mode, and the defect has no effect on performance.
However, last time I checked, a lit Check Engine Light, or one that fails to light and go out when starting the engine, is an MOT failure.
I can confirm with a missing/faulty post main cat sensor the Roadster will still run fine and produce healthy power figures - mine is currently like this.
FWIW, having checked my post-main cat sensor, the original one had failed due to an open-circuit heater circuit on it - my roadster probably had been sat at motorway speeds with little/no thorttle and the ECU would have been keeping the O2 sensor heaters on to get readings from them.
One other thing to add - Generic O2 sensors don't seem to work as well as Toyota OEM sensors - I swapped my Toyota O2 sensor for a generic one and it caused the car to run worse than normal (and the hesitation to be more pronounced at times) - this may be also due to the fact that I only have ne precat O2 sensor feeding both ECU inputs. I'm seriously thinking about modifying the PE turbo manifold to go back to having two o2 sensors, just like the Hass Turbo kit.
Quote from: "BenF"Quote from: "GSB"Quote from: "heathstimpson"Quote from: "phil4"Quote from: "aaronjb"IIRC - don't think a CEL will fail an MOT).
By itself, I think you're right, but if the CEL is caused by the emissions being out of line, I guess there's a chance you'll fail the MOT emissions check.
I believe this is right Phil and the third sensor is not just a static level monitor but also controls the levels going into the cat. Anyone to confirm s:?: :?: s:?:
Third sensor has no control functions at all. It is simply used by the ECU to monitor the performance of the cat. It does this by comparing the signal from the 3rd O2 with that of one of the primary O2 sensors in the manifold. If you were to hook an oscilloscope up to the sensors in the manifold, you'd see that the O2 content isnt in fact stable, it oscillates around the "ideal" point, going high, then low, then high again, forming a square wave. The actions of the catalysts will even this oscillation out, giving a far steadier signal at the 3rd O2 Sensor IF they are working properly. If the cats are dead (or missing) and are having no effect, then the signal at the 3rd O2 will match the one at the primary O2 sensors in the manifold.
This matching signal is then recognised as a fault, and the Check Engine Light (CEL) is lit, and a code stored in the ECU memory. Thats as far as it goes though, unlike a failure of a primary O2 sensor, which causes the engine to revert to a "safe" open loop mode of operation, a 3rd O2 sensor failure is not safety or operation critical, and thus the engine management remains in its normal mode, and the defect has no effect on performance.
However, last time I checked, a lit Check Engine Light, or one that fails to light and go out when starting the engine, is an MOT failure.
I can confirm with a missing/faulty post main cat sensor the Roadster will still run fine and produce healthy power figures - mine is currently like this.
FWIW, having checked my post-main cat sensor, the original one had failed due to an open-circuit heater circuit on it - my roadster probably had been sat at motorway speeds with little/no thorttle and the ECU would have been keeping the O2 sensor heaters on to get readings from them.
One other thing to add - Generic O2 sensors don't seem to work as well as Toyota OEM sensors - I swapped my Toyota O2 sensor for a generic one and it caused the car to run worse than normal (and the hesitation to be more pronounced at times) - this may be also due to the fact that I only have ne precat O2 sensor feeding both ECU inputs. I'm seriously thinking about modifying the PE turbo manifold to go back to having two o2 sensors, just like the Hass Turbo kit.
and the TTE for whatever thats worth.
Firstly, decatting should not throw a CEL. Be sure to reset the ECU. If the CEL comes back, then something in the procedure gang aft aglay, as the mice and men would have it.
Secondly, GSB is a God. In my fondest dreams I have a fraction of his knowledge.