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C8 2.0 Petrol Throttle Position Sensor Error, Anti Pollution Fault


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Hi All,

 

So my c8 is the 2.0 liter petrol version. Automatic year 2003. 

 

Been having this error popping up every now and then

 

P0121

Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

 

the anti pollution fault comes up everytime that error comes on, i have a scanner to see the error and usually erase it and it goes off only to come back a few days later. Thought it was the throttle body at first and have took it out to clean and etc. Was working fine for a while and it popped up again and again now. The idle goes crazy when the error pops up.

 

Problem is I can't seem to bloody locate the throttle position sensor. Where on earth is it? i looked all over the throttle body but the sensor isn't there. I got the part from the shop and this is the diagram that shows where the tps should sit at  which that highlighted no9. 

 

http://shooshoomoo.com/c8/tps.jpeg

 

But on my throttle body theres nothing there when i took out the air intake. only the ones which i've circled A.B and C

 

http://shooshoomoo.com/c8/1.JPG

http://shooshoomoo.com/c8/2.JPG

http://shooshoomoo.com/c8/3.JPG

 

Where on earth is it?!?! 

 

thanks!

 

 

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The part 9 you have highlighted seems to be part 1920Y8 with name reheating unit so it is probably not the throttle position sensor. Possibly the sensor is built in to the throttle body so a complete unit may be needed.

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I have attached a photo of the TPS location on my Citroen 8 (it is 2.0 diesel). It is NOT the grey connector near the tip of the arrow, it is behind it.

If you put your hand in the gap between air purifier and (behind) the vacuum sensor, you will see and feel the TPS and the accelerator cable.

You can ask someone to press the accelerator pedal while touching it, to confirm.

post-91625-0-55908600-1470042675_thumb.jpg

Edited by Simple
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ok just went back to the sparepart shop and he keyed in my engine number and still the same diagram popped up however my throttle body doesn't have that part which leads me to believe that there's something wrong here, the one on his computer says its a 16v engine, but from the looks of my throttle body it looks like the 8v version which doesn't make sense because he put in my engine number in to the system. http://www.buycarparts.co.uk/vdo/1736716  << this is what i found online. 

 

My mechanic said that the throttle body is built in, like you mentioned, so it could be the link i found which looks like the right match, but the spare part shop told me to remove the throttle body and look for any number on it, i kinda opened up the airfilter and i couldn't really find any distinct number on it, and from the pics below, it definitely doesn't have the no9 sensor that i bought intially. 

 

So what should i do? im not sure which one should i go for. 

 

From the pics below you can see the back part of the throttle body does not fit the sensor from the diagram and from the link i found online, it looks like a direct match to the 8V model.

 

http://shooshoomoo.com/c8/4.JPG

http://shooshoomoo.com/c8/5.JPG

http://shooshoomoo.com/c8/6.JPG

http://shooshoomoo.com/c8/7.JPG

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I have attached a photo of the TPS location on my Citroen 8 (it is 2.0 diesel). It is NOT the grey connector near the tip of the arrow, it is behind it.

If you put your hand in the gap between air purifier and (behind) the vacuum sensor, you will see and feel the TPS and the accelerator cable.

You can ask someone to press the accelerator pedal while touching it, to confirm.

ah great thanks for this, i'll go down now and give it a check.

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ok great i think i found it, is this the one Simple?? that does look like a throttle position sensor doesn't it?

 

http://shooshoomoo.com/c8/8.JPG

http://shooshoomoo.com/c8/9.JPG

http://shooshoomoo.com/c8/10.JPG

http://shooshoomoo.com/c8/11.JPG

http://shooshoomoo.com/c8/12.JPG

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Yes, that's the one..

Before dismantling it try to clean the connector. You could also adjust the link position (there is a springy stopper, you can see it in the 3rd photo), it may also help.

If it does not work, you may try opening it and lightly spraying it with (preferably) "Switch or Contact Cleaner" (you may also use alcohol and a soft brush); in case there is dirt causing errors.

Avoid 3 in one oils or abrasive sprays on the sliding contacts parts.

Edited by Simple
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For future use, you can see the Citroen parts diagrams as a free service and use your VIN (VIS) to find your car and the parts on it, rather than relying on third parties or things you may see on-line. You need to register on service.citroen as an other professional non emergency services and as a member of the Citroen Owners Club http://service.citroen.com/do/changerParametres You may need to select your language first, then once on the diagrams use your VIN (VIS) top left to find your car. Look under Mechanical, Air and fuel supply, to find the various sensors. If you look under Characteristics it will give you info on your car.

 

Any part numbers you find on parts are the manufacturers and not the Citroen ones, so if you did find any numbers on them they may not be of much use.

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For future use, you can see the Citroen parts diagrams as a free service and use your VIN (VIS) to find your car and the parts on it, rather than relying on third parties or things you may see on-line. You need to register on service.citroen as an other professional non emergency services and as a member of the Citroen Owners Club http://service.citroen.com/do/changerParametres You may need to select your language first, then once on the diagrams use your VIN (VIS) top left to find your car. Look under Mechanical, Air and fuel supply, to find the various sensors. If you look under Characteristics it will give you info on your car.

 

Any part numbers you find on parts are the manufacturers and not the Citroen ones, so if you did find any numbers on them they may not be of much use.

 

i can't seem to find the register button though, do you know where i can register? 

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Or you could download the "Citroen Service Box + Sedre" using the torrent within the attached zip file. It is 20 GB though..

If you don't have a Bit Torrent client, I reccommend qBitTorrent from (http://www.qbittorrent.org/). It is free with no adverts.

 

You could install all software belonging to the car within a Virtual Machine like VMware Player or VirtualBox, it is tidier and they are also free.

Citroen Service Box (DocBackup + Sedre) (11.2013).torrent.zip

Edited by Simple
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thanks for the link to the torrent files, im gonna download it today.

 

I just replaced the tps sensor, 3 days ago and now the same damn error popped up again.

 

P0121 is the error that keeps popping up, and then the anti pollution fault comes on as well. After that the car goes into limp mode and the idle seems erratic again. Sometimes its ok after i switch it off and restart or i have a generic obd 2 reader that i plug in and erase that error, and restart the car again, it will work fine it takes a minute or so for it to get readjusted of course. 

 

Im completely annoyed now cuz i just sent it to the workshop to replace that sensor and the same bloody error keeps coming on! I've got no confidence bringing my family in this car anywhere as it will just suddenly go into limp mode when that error pops up.  :unsure:

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Your issue may be a result of badly synchronized information going to the ECU due to faulty component or bad connection, causing the ECU to produce the error and reducing power to save engine.

 

Ensure the spark plugs, coils and cables are all in good order. Also check your MAF is clean and in good order.

 

Good luck.

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spark plugs are new, haven't checked the coils and cables tho. But if the coils were faulty wouldn't the check engine light appear and show the error? 

 

i do have a dodgy ignition though, i need to turn the key 3-4 times before i can start the car. Would that be related?

 

Also looking at the ground cables too, read on the sticky post that corroded grounding cables can cause electrical madness too. 

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ok just now few errors popped up again!

 

P1133   HO2S 1 Insufficient switching

P1112   Intake air temperature (IAT) sensor circuit Intermittent low voltage

 

 

i don't think all the sensors are busted though........something is severely wrong here. im gonna check the ground cables, but besides that im not sure what else can i do about this. Would a weak battery cause this?

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Most modern cars have a lot of sensors that may go wrong themselves or produce erroneous readings/outputs due to bad connections or interference. The most difficult faults are the intermittent ones that happen unpredictably and when you connect your diagnosis tool they disappear, like a chaffed wire that touches a ground when taking a corner or a connector that is not plugged properly that occasionally may not allow for full current flow or something like that. Ensure that all moving parts (like flaps) are actually moving without restrictions..

 

Since you already know that the ignition has something wrong with it, I would advise that you start there.. A can of Switch Cleaner spray may prove to be a good investment. You may have an intermittent loss of power to the sensors due to dirty or worn out contacts that is causing the whole thing. 

 

Oh, and something else, do not go changing parts without testing them first.. it would prove too costly. Also a generic diagnostics tool would not provide you with the capabilities of Citroen's (DiagBox/Lexia) specific tool nor the ability to re-program the various devices in the car.

Edited by Simple
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The P1133 might suggest the inlet lambda sensor is faulty (or its wiring) and the P1112 might suggest the MAF sensor or its wiring is faulty. You could start checking the connections at the sensors and the ecu. If you had a code reader that does live data you could see what values the sensors are giving to help with your diagnosis. The IAT should be ambient temperature before starting the engine but then may go up a bit so yuo should be looking for values from about 10 to 30°C. The inlet lambda sensor should be about 1.0 and switch every second or so by a small amount as it adjusts the fuelling. The outlet lambda sensor should be steady if the catalyst is ok but if this has a problem the running is not normally affected, unlike the inlet one.

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ok thanks, another error popped up again, this time its the same P0121

Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

 

but together with a new error which is this one >> 

 

P1153 Bank 2 Fuel Control Shifted Lean 

 

I've ordered a lexia-3 diagbox from ebay and waiting for it to arrive to diagnose it properly. 

 

The anti pollution error keeps coming on almost every other day after i erase the error with the generic reader. I really don't think all the sensors are busted. This is annoyingly frustrating. 

 

I kinda check some wires that i can see in the open and it seemed fine. Checked connectors as well and looks fine too. 

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Larger diameter screws or bolts and nuts could be used to fasten the air filter lid, probably a previous owner has tightened the original screws too much and stripped the plastic threads in the box. I do not know if this would affect the running but since it is easy enough to fix it should be done to prevent dirty air entering the engine.

 

A search came up with P1153 Bank 2 Fuel control shifted lean. MM6LP - Throttle stop learning. Malfunction - so it may be related to the TPS problem or the lambda sensor.

 

You should also check the battery voltage since a low voltage sometimes gives odd electrical problems on Citroens (as well as other makes). Should be about 12.7 volts before the engine is started and then about 14.4 volts once running.

 

If your engine is the hpi version then it has some specific fault codes with definitions that differ from generic ones. This topic has some listed and includes some you are having http://www.citroen-owners-club.co.uk/citroen/topic/6461-02-sensor/

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Larger diameter screws or bolts and nuts could be used to fasten the air filter lid, probably a previous owner has tightened the original screws too much and stripped the plastic threads in the box. I do not know if this would affect the running but since it is easy enough to fix it should be done to prevent dirty air entering the engine.

 

A search came up with P1153 Bank 2 Fuel control shifted lean. MM6LP - Throttle stop learning. Malfunction - so it may be related to the TPS problem or the lambda sensor.

 

You should also check the battery voltage since a low voltage sometimes gives odd electrical problems on Citroens (as well as other makes). Should be about 12.7 volts before the engine is started and then about 14.4 volts once running.

 

If your engine is the hpi version then it has some specific fault codes with definitions that differ from generic ones. This topic has some listed and includes some you are having http://www.citroen-owners-club.co.uk/citroen/topic/6461-02-sensor/

thanks yeap im still waiting for my lexia diagbox to be delivered....sigh....taking ages to get here.........

 

I did discover some new issues as well, my throttle pedal seems to be slightly broken, but it kinda works still. would this be one of the causes as well? is there any sensors connected at the bottom of that throttle pedal? so far i couldnt see any. 

http://www.shooshoomoo.com/c8/pedal.JPG

 

and then i started messing with the cables highlighted below, at one point while the car was switched on, i pushed it and the idling just died completely then restarted again and retried it but i couldn't get the idle to die off again, which leads me to believe that possibly there's some dodgy wire in there thats causing this. Is it easy to re-wire that ? its kinda hard to trying to pinpoint which dodgy wire thats causing the sensors to go haywire cuz its all wrapped up together. 

 

http://www.shooshoomoo.com/c8/wire.JPG

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  • 3 weeks later...

thanks for the help! i've figured it out after weeks of trial and error and trying to get lexia to work, i went down again yesterday and started the engine, i erased the error with lexia, and then i pushed the cables highlighted above and it died immediately the check engine light with the same error popped up. So now im very very sure it''s the wiring that goes into the throttle body.

 

 

Question though, is there anywhere that i can buy that wiring loom online? Or do they not sell something like that?

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You should be able to fix this problem if it is wiring, you need to ascertain first if it is broken wire (inside the plastic coating, due to vibration), chaffed wires touching (due to friction or heat) or a loose connector at the end of a wire (due to rust/tarnish/salt/deposits).

 

Notice that the wires are squeezed together before entry to the box, it may be wise to space them a little and spray them with WD40 or some water repellent; first. (do not bend the wires much, while testing, you could end up with more broken ones).

 

P.S. If when you pushed the wires they moved inside the box, your problem may be a bad connection or a dry joint on the board that needs re-soldering. opening the box may confirm.

Edited by Simple
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  • 7 months later...

ok the damn anti pollution error is back again. Since my last discovery i thought that the wiring was causing the issue, but it was actually the wire that connects to the aircon compressor that causes the idle to get slightly dodgy when i push the whole bunch down, it actually was stopping the compressor which made the idle drop a little bit. So the problem was not the wiring. I've fixed the airconditioning wire since and it was fine. 

 

Right after i fixed the aircon wire, something really bad happened, my power steering pressure switch was leaking all this while little by little and pouring into the alternator and for the last 6 mths its been doing that i didn't realise it until one hot day, the alternator started catching fire and my car was basically covered in smoke, thank goodness i had a few bottles of water in the back and emptied it onto the alternator, to be honest i actually thought the car was gonna explode. Anyways sent the car back, got a new alternator, new power steering switch and voila, back to normal again, surprisingly no more idling issues, no more errors, this lasted for at least 3 mths until the last two weeks again the damn error started popping up again. 

 

This is really starting to piss me off, same error pops up P0121 error (Anti pollution error) my idle is starting to get erratic as well again. 

 

Only thing i haven't checked now is the earth cables, but i cant believe its that as the car has been fine for 3 mths so why all of a sudden its acting up again? 

 

Very close to ditching this car and selling it off really. Went through lexia saw some errors but couldnt really tell what it was and im just not really experienced enough on what i need to do when im on lexia. 

 

So what do i do now? Blow up the car and claim my insurance?  B)

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