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You can monitor the O2 sensor voltages with your OBD tool. If fact it's better to do that initially, because that will show you what the ECM sees as the voltage.
As @Vee says above, if the ECM is not seeing anything then you will need to measure at the actual sensors and you will need multimeter for that (you definitely need a multimeter anyway ).
Here's some sample screenshots with the Autel tool.
1. Start position. Engine just started. OL, O2 voltage low, STFT 0
2. 20-30 seconds after engine start. OL, O2 voltage now rising to high as it warms up. STFT 0
3. Induce a Lean condition (by pulling off Vac pipe on inlet manifold. O2 voltage drops but STFT stays 0 as in Open Loop.
4. Just entered Closed Loop. O2 volts high, STFT just starting to move to -ve.
5. Normal operation at idle, Closed Loop. O2 voltage moves high and low. STFT flexes slightly as O2 voltage changes.
Excellent example but my Autel isn't showing the voltages, it shows just the trims. I have to read the OBD with the "OBD- function" of the AP200, I can't do much which the Jaguar-specific software. Its always giving me an error.
I contacted Autel but they weren't helpful.
Last edited by Slazenger7; 10-01-2021 at 03:13 AM.
1. I always recommend D900 over ELM as cheapo OBD scanner. Works perfect with X300, shows o2 sensors too and you might be able to get it in Germany too.
2. Measuring o2 sensors directly with a digital multimeter isn't going to do much, you can just about measure 5 or 0V, you wont be able to check for switching, which is important here. You'll need an oscilloscope or an old school analogue meter to do any kind of meaningful troubleshooting.
3. CTS at under 80C is fine.
4. You'll probably have to fork out for new sensors, they are old and lazy anyway and suppose to be changed. My guess is that heaters are shot hence they don't 'close' anymore.
5. You can definitely do it yourself, you can get to one from the engine bay, just cut off the wires as low as possible, then normal socket over it and 4 or 5 extensions and it will come out. The other one can be accessed from underneath the car, you will need to get it up enough to actually get underneath it, normal spanner will get it out although open ring spanner is preferred.
6. I highly recommend getting a tap and rethread the hole after removing old o2 sensor. They are often messed up and it easy to cross thread new sensor.
7. You wont pass your test until the o2 sensors show closed loop. Good luck.
I guess you are right. 88 degrees C motor temp isn't needed for closed loop because the heater heats them up to 700 degrees C in 20 seconds. They may be kind of working electrically, but still old and shot/heater not working, slow etc. Instead of using penetrating oil or rust remover the mechanic should use a torch to get them out. I read that oil etc destroys the sensors. I have some ceramic paste at home. We will use this for re-installation.
Thanks
Last edited by Slazenger7; 10-01-2021 at 03:12 AM.
Excellent example but my Autel isn't showing the voltages, it shows just the trims. I have to read the OBD with the "OBD- function" of the AP200, I can't do much which the Jaguar-specific software. Its always giving me an error. :-(
I contacted Autel but they weren't helpful.
The voltage is NOT Jaguar specific, it is general ODB data so you should be able to view it. Is it not come in up as an available selection under live data?
Excellent example but my Autel isn't showing the voltages, it shows just the trims. I have to read the OBD with the "OBD- function" of the AP200, I can't do much which the Jaguar-specific software. Its always giving me an error. :-(
I had the same problem too. However, if you use the OBD function rather than Jaguar, and also select the protocol manually (ISO 9141-2) then you should see the voltage option. That's how I found it.
I guess you are right. 88 degrees C motor temp isn't needed for closed loop because the heater heats them up to 700 degrees C in 20 seconds. They may be kind of working electrically, but still old and shot/heater not working, slow etc. Instead of using penetrating oil or rust remover the mechanic should use a torch to get them out. I read that oil etc destroys the sensors. I have some ceramic paste at home. We will use this for re-installation.
Thanks
OK, I read my manual, and it appears that 82C is the specified thermostat temperature. That is completely different than the oxygen sensor temperature. Both are needed to get to closed loop. It doesn't say at what temperature the coolant needs to be to check that box though....I may have that info somewhere...
Silicone kills oxygen sensors, not oil. (also, apparently whatever they use to make anti-seize) Oil and other petroleum products, I would suspect, are fine for an oxygen sensor, after all, it's being set in an exhaust where that's all it breathes for its entire useful life!!!
good morning or good day, I enjoyed my sunday with scratching my fingers to swap the O2-connectors (thanks to Jaguar for making the wires just a little too short), also put some contact spray in it. the OBD showed no changes in voltage = flatline. So my O2's are pretty dead. No significant change in idling before/after swapping, still pretty smooth with defective sensors. I guess the car starts shaking with functioning sensors, which are connected the wrong way. I will ask the mechanic to heat up the exhaust around the sensors to break them free.
I let the engine idle and tested the thermostat:
- 62 C the hose near the thermostat housing warms up, lower end to radiator still cold
- 65 C both hot
conclusion change the thermostat? It should open much later?
I don't want to spill coolant on the belts and I have a little water pump. Can I suck out enough water from the reservoir to avoid the spilling? Can you please tell me the torque for the thermostat housing and the O2-sensors (45 Nm?!)? I have a torque wrench for wheels. I heard "Behr" makes good thermostats or is there a special Jaguar-one at british parts? I would order this right away.
Thanks
Last edited by Slazenger7; 10-04-2021 at 02:13 AM.
I bought ramps and was able to change one sensor from underneath. No heat (wanted to use my heat gun but its broken) and a just a short wrench (30 yrs BB finally pays lol) – > NTK Lucas from 1996. Totally gone and rusted away. I managed to spin the other one slightly from above with pliers and then injured my hand. I have an 1/2 torque wrench but need an extension to get that ol’ bstrd finally out.
Not sure if I got the torque of 16 Nm right on the first one. Short wrench and not too much force → tight and then some more :-)
Last edited by Slazenger7; 10-31-2021 at 07:37 AM.
The extensions arrived and I was able to change the last sensor. That was a major pain in the a$$.
After that I plugged the OBDII fault reader in. The volts on Bank 1 and 2 are changing now 1,27 V in idle and lower (0,47 for instance) when I hit the throttle. The SFT and LFT are still dead due to insufficient engine temperature. Its cold in germany and the car gets only to 79 degrees C at idle. So i pulled the two fan fuses and it rose to 94 degrees C. I still get the message open loop due to insufficient engine temperature.
I don't know what to do now. I need to pass MOT urgent, because its overdue since February. :-( I need to log off my car now.
One guy had the same problem and he stated that he plugged his car to VCM/IDS and did adaptation for the O2-sensors, gas pedal and TPS and the car went to closed loop. Im in germany and NO ONE seems to have that, at least not in the reach of about 600 kilometres. :-(
Is there any way to do this at home? Reset the ECU? Maybe pull the fuse or something? I need to sell the car if I don't find a solution quick. :-(
Thanks guys, I appreciate your time and help.
Last edited by Slazenger7; 11-08-2021 at 03:24 AM.
I can’t remember if you had eliminated the engine temperature sensor as a cause, but would mention when I got my 3.2 Sport from a friend a few months ago he had recently replaced that sensor in relation to rich fuel issues.
When my local garage found an OBD2 scanner old enough to read X300 codes, the new sensor started at ambient temperature, correctly, recorded increasing temperatures then when it reached about 90 degrees C, suddenly told the scanner and ECU that the temperature was about minus 40 c.
A replacement sensor from SNG Barratt solved that problem, tho it still looks as if my O2 sensors are failing.
I can’t remember if you had eliminated the engine temperature sensor as a cause, but would mention when I got my 3.2 Sport from a friend a few months ago he had recently replaced that sensor in relation to rich fuel issues.
When my local garage found an OBD2 scanner old enough to read X300 codes, the new sensor started at ambient temperature, correctly, recorded increasing temperatures then when it reached about 90 degrees C, suddenly told the scanner and ECU that the temperature was about minus 40 c.
A replacement sensor from SNG Barratt solved that problem, tho it still looks as if my O2 sensors are failing.
Best of luck
Alan
Hi Alan,
thanks, I bought a new temperature sensor. Also I shorted the sensor (and some others) to force the temp up. Nothing changed. Doing the drive cycles now. ;-)
As suggested by Parker I checked the 10amp fuse for the 02 heaters which was intact
I invested in a £7 ELM 327 clone and loaded free Carscanner on my iPhone and got some readings.
On a borrowed one a few days back we couldn’t produce a MAF reading > 0g/sec
After a spray of the MAF wire and the mesh in front of it I now get as per graph
Assume units wrong by 100 but at least a reading Bank1 sometimes not moving and consistently lagging below Bank2. Neither moving anywhere near 4v and both slow to move.
I’ve bitten the bullet and ordered 2 pattern O2 sensors from Britparts. The MAF was the original from 1996 so will be interested to see how the sensors are.
I did notice that hardly any additional engine revs were required from tickover to boost both sensors to 24% which then slowly dropped down on lifting off the throttle.
Idle TPS is 13/14%
I guess its not, the instrument cluster is normal (middle). Only the ELM states otherwise. I guess its the not completed drive cycle. Have done a few runs with no luck. Some say put AC and rear defroster ON at idle, then OFF for the readyness of the O2 heaters. Is that correct?
AC and all the other electrical stuff OFF while doing the drive cycle seems right?! But why? :-)
ELM states what? The sender uses a different sender. The data the ELM provides is important since it is what the ECU sees. The instrument cluster is irrelevant.
The instrument cluster temp gauge uses the single wire temp sender
The ECU uses the 2 wire temp sensor next to it on the thermostat housing and that is the one of focus for your issue
you can only use the instrument cluster gauge to give you " some " information like if the thermostat valve is failed to the full open position and not allowing the coolant to warm up which you can see is not your observation
but if you do tinker with the thermostat, it does not take a o - ring ( even if a new one comes with one ) as it cracks the thermostat housing
There is the possibility that the thermostat is regulating the coolant temp just below the 88 degree C and a new thermostat is not always good out of a store box ( Bad from stock )
So the focus is the 2 wire sensor reading before considering out of a list of other variables in the coolant system replacing the thermostat
In the bigger picture of your engine regulation have you looked into your EGR valve if you have one ?
You can pull up a EGR _ERROR value with the ELM - 327 and your target is 0 %. just cleaning the poppet seat has recovered some idle performance
The secondary air pump ( smog pump ) if installed only runs for 60 seconds and there is a history of that failing as there is a relay , fuse , diode , a check valve in the air line and the pump itself which also has a check valve inside
cracked exhaust manifolds ?
Loose or worn 2 donut gaskets just below the exhaust manifolds ? best tightened from below , 15 mm socket on a long extension
10-01-2021, 03:01 AM
