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Citroen Saxo 1.1 HFX 2001 - MOT emission failure, code P0108 MAP sensor high input - Fixed #

Posted by Liam Hall on September 9, 2011, 8:22 am

Year of Manufacture *: 2001 51
Engine Size and Code *: 1.1 HFX
( Optional ) Scanner Used: SOLUS PRO
( Optional) Fault Codes: P0108 MAP SENSOR HIGH INPUT

Hi all, just after a little advice.

This car has come in after failing the mot on emissions.

I have scanned the car and P0108 - Map sensor circuit/high input was showing.

Question is, would this give me the following emission data?;

(FAST IDLE)

CO: 9.247%
HC: 555ppm
LAMBDA: 0.731

CO: 8.543%
HC: 547ppm
LAMBDA: 0.747

I have checked for air leaks etc and everything is good.
Live data the lambda sensors are switching, but I dont do enough on petrols to know if they are right!?

Pre cat goes from 0.06 to 0.69. is this what i would expect?

Thanks in advance!

Liam.

Re: Citroen Saxo

Posted by Lee Mackintosh <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1348' width='330' height='300' border=0 style='border:none;'> on September 9, 2011, 8:47 am, in reply to "Citroen Saxo"
Lee Mackintosh

If you haven't already check the multi-plug pins for the map sensor, had one recently that had this fault code due to a poor connection.

A wiggle test may show up a fualt as well. The car we had in was cutting out and wouldn't idle.

Re: Citroen Saxo

Posted by Liam Hall <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3033' width='330' height='300' border=0 style='border:none;'> on September 9, 2011, 8:49 am, in reply to "Re: Citroen Saxo"
Liam Hall

the weird thing is this idles perfect!

Re: Citroen Saxo

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 9, 2011, 12:47 pm, in reply to "Re: Citroen Saxo"
Mark Carter

Whats the MAP reading KOEO and KOER ?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Citroen Saxo

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on September 9, 2011, 3:10 pm, in reply to "Re: Citroen Saxo"
Peter Mutlow

Hi Liam,

I assume the gas readings are OK at idle. The HO2 sensor should be reading a bit higher at approx 0.8v (peak) and switch at about 1 htz or lower at fast idle. Scoping the MAP sensor will give you sufficient evidence if it is faulty. The answer to Marks question would also be interesting. From this end of the lap-top sounds like a MAP sensor problem given the facts provided so far.

Regards

Pete M

Re: Citroen Saxo

Posted by Bryan Smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5330' width='330' height='300' border=0 style='border:none;'> on September 10, 2011, 1:57 am, in reply to "Re: Citroen Saxo"
Bryan Smith

Hi Liam,
Mark will only ask relevant questions that make you think about the problem and enable you to learn in the process. In other words I would be sure that he knows how to test the MAP but wants you to find out how to do it.

"I have scanned the car and P0108 - Map sensor circuit/high input was showing.
Question is, would this give me the following emission data?;
(FAST IDLE)
CO: 9.247%
HC: 555ppm
LAMBDA: 0.731

CO: 8.543%
HC: 547ppm
LAMBDA: 0.747"

I will put my head above the parapet and say that you have far too much fuel and not a misfire?
A MAP is an important load sensor in as much as that, at WOT you will have minimal manifold depression and at idle or on overrun you will have maximum. WOT requires lots of fuel, therefore if the PCM sees a lack of depression it will chuck in loads.
I think that what Mark is trying to do is get you to look at what the PCM thinks is happening in the way of the message it receives from the MAP. Have a play around with a multi meter on the MAP pins and post the results.
Regards,
Bryan
PS, sorry if you are aware of this but only do resistance tests with the component disconnected.

Re: Citroen Saxo

Posted by aidan birley <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on September 10, 2011, 7:58 am, in reply to "Re: Citroen Saxo"

Liam

quote >>>>> Live data the lambda sensors are switching, but I don't do enough on petrol's to know if they are right!? <<<<<

To be honest with those gas readings and with the engine RPM steady I would expect the O 2 sensors to be stuck high at around 0.8v and not switching.

It would be good if you would confirm this as result may change the diagnostic route.

Clearly the MAP fault code needs checking first, at what point does that code re appear after cleaing? as mark asked live reading at key on and idle as needed next.

Cheers Aidan

Re: Citroen Saxo

Posted by Liam Hall <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3033' width='330' height='300' border=0 style='border:none;'> on September 12, 2011, 2:28 pm, in reply to "Re: Citroen Saxo"
Liam Hall

Thank you very much for the replies guys, I am grateful for you having the willingness to help me/others learn.

Got some more time on the car and the results are as follows;

MAP at KOEO: 1000mBAR
KOER: 600mBAR (idle)
WOT: 180mBAR
2500rpm: 340mBAR.

I also used a multi meter on the map sensor and got two readings -

Pins 1&2 5.9 ohms
Pins 3&4 1.7 ohms

I beleive pins one and two are for IAT and three and four are for MAP?

I have just this minute compared the resistance on a 206 with same map sensor (numbers match)
and 1&2 were the same, but 3&4 were 2.5 ohms on the 206.

Have I found my problem? I think so, but clarification would be nice.

Also I cleared the code and it comes back immediately without starting the car, so surely I have a closed circuit in the MAP sensor?

Thanks again,

Liam Hall.

Re: Citroen Saxo

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on September 12, 2011, 7:43 pm, in reply to "Re: Citroen Saxo"
Kevin Apps

Liam
Did you post the MAP figures correctly ?
and did you check them with a gauge ?
Kev.

Re: Citroen Saxo

I'm with Kevin,

Did you get these figures from live data or a vac gauge?

Regards Mark

PS. after reading your very first post I think you may have tested the MAP sensor correctly. (9 odd Percent)

Modern cars, Its all wizardry and witchcraft

Re: Citroen Saxo

Hi

Another point worth noting is if there is a permanent fault logged for MAP circuit, any live data may be an ECU estimated value rather than true reading.

cheers aidan

Re: Citroen Saxo

Posted by Bryan Smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5330' width='330' height='300' border=0 style='border:none;'> on September 12, 2011, 10:52 pm, in reply to "Re: Citroen Saxo"
Bryan Smith

Hi Liam,
Acccording to Vivid, pins 3 & 4 are IAT. If that is correct and the two sensors were tested at different temps that could explain the difference.
HTH's
Bryan.

Fixed #

Posted by Liam Hall on September 13, 2011, 6:06 pm, in reply to "Re: Citroen Saxo"
Message modified by board administrator September 22, 2011, 1:02 pm

Got this one fixed today.
Fitted a new map sensor and it was as right as rain.
Also had the wrong spark plugs in - not too sure if that was causing a problem?!

Again, thanks for the help and info, I find that you
guys 'nudging' me to think about the problem is really helpful.

Liam.

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