C5 Fault code P1113

[rsdavies]

Further to my post C5 cutting out.
Does any one actually KNOW what the fault code P1113 means?
Its a 2 Lt HPi. RAC diagnostic gizzmo came up with this code and no info available, RAC HQ say it means air intake sensor local citroen dealer technical department won't help unless they have read the code for them selves.
the haynes book says this sensor is an integral part of the throttle housing this is not the case on my 52 plated car , all you have to do is squeeze the claws in on the inside whilst gently pulling from the out side, at £8.75 from my local parts house it is a good starting point. Haynes say the range is between 2500 ohms @20c to 340 ohms @ 80c, the engine runs quite ok but with warning lights with this sensor disconnected, a 900 ohms resistor puts the warning lights out, and they stayed out when it was removed, didn't risk driving it any where should have the new sensor Monday evening.

[myglaren]

Take a look here:
BBA_Reman

It confirms what you said, "P1113 Intake air temperature (IAT) sensor circuit open/short"

On mine it appears to be integral with the MAF -



Just visible at 11 O'clock.

(click the thumbnail, then the larger image for full size image)

[MikeT]

Did you test your IAT is out of spec? The fault codes are more a hint than a direct pinpoint and when it refers to a component, the complete circuit also needs to be considered. It's quite common for Citroen connectors to just need a wiggle to make proper contact and that could be reported as an Open/Short.

What you may find that fitting a new IAT cures the problem but it wouldn't have been the cure. So doing it your way means you get two chances of fixing it instead of one.

[rsdavies]

My local parts supplier, didn't do as he said so I don't get the replacement sensor until tomorrow. It certainly detaches from the throttle housing though, I'll send pictures as I change it. Thought of replacing the whole circuit fills me with dread, I knew from past experience that citroen wiring can be suspect. The old sensor was giving a reading of 3500 ohms and it was cooler than 20c today with it up at 25c it was reading 2050 ohms so it seems to be working but if it is working right I cant tell, it could just be that in removing it I've made a better connection inside it.
There is the possibility of black wire corrosion, and the wires to the connector are exposed for about 10mm (that is the inner insulation not the actual copper) before they go into it. I'd prefer it if the outer insulation was one with the body of the connector, and I've read reports of all the connections being replaced on a DS23 to make the fuel injection behave.
Enough looking for problems it seems to work better when it is cold, and it did first happen on the hottest day of the year since I've owned it.

[MikeT]

Thought of replacing the whole circuit fills me with dread, I knew from past experience that citroen wiring can be suspect. The old sensor was giving a reading of 3500 ohms and it was cooler than 20c today with it up at 25c it was reading 2050 ohms so it seems to be working but if it is working right I cant tell, it could just be that in removing it I've made a better connection inside it.

Don't worry, you won't need to have the complete circuit replaced, I was just hinting that the fault could be a broken wire or ill-fitting connector rather than the IAT itself, but if you're getting readings that are out of spec then you're probably on the right track.

It would be helpful if you can get confirmation of what should be the correct resistance range of your IAT, as the Haynes can't be wholly trusted as accurate. Perhaps another forum member can help?

[wheeler]

The IAT sensor is an NTC type.

resistance at 20 °C = 2500 ohms (approx)
resistance at 80 °C = 310 ohms (approx)

[MikeT]

The IAT sensor is an NTC type.

resistance at 20 °C = 2500 ohms (approx)
resistance at 80 °C = 310 ohms (approx)

BoL was close enough!

Seems to me like the IAT is working within spec then. It is still possible it could be intermittently going OPEN/SHORT but I wouldn't rule out a poor connection or contact somewhere in the wiring.

[rsdavies]

Changing th 'faulty' sensor took all of 10 minuets car got me to work and to with in a mile of home. RAC gizzmo came up with a whole list of fault codes this time, original one is still there, new ones all relate to throttle sensor and or throttle circuit.
Only plus side is because it was un fixable by the road and they had to tow me home the RAC will flat bed it to a main dealer or bosch service centre, mean time I could try taking the cover off the back of the throttle sensor and cleaning all the contacts. After all if the bosch center or main dealer are going to fit a new one what have I to lose.

[cachaciero]

FWIW The documentation I have says that the engine ECU uses the outside airtemp sensor in the mirror as a backup to the Air Inlet Sensor whether that is a backup as in the average of the two or as in a comparison to check that the AI sensor data is good I don't know.

Cachaciero

[cachaciero]

Changing th 'faulty' sensor took all of 10 minuets car got me to work and to with in a mile of home. RAC gizzmo came up with a whole list of fault codes this time, original one is still there, new ones all relate to throttle sensor and or throttle circuit.
Only plus side is because it was un fixable by the road and they had to tow me home the RAC will flat bed it to a main dealer or bosch service centre, mean time I could try taking the cover off the back of the throttle sensor and cleaning all the contacts. After all if the bosch center or main dealer are going to fit a new one what have I to lose.

Given your concerns about the quality of Citroens wiring I would strongly suggest that a good course of action would be to re-seat all connections to the engine ECU and while you are there( Mk1) the throttle sensor for good measure. Having said that IMHO the standard of wiring on the C5 is better than some of it's predecessors.

Cachaciero

[rsdavies]

Local Citroen main dealer is now trying to sort this, they are saying their diagnostics point to the High pressure regulator, as apparently the fuel supply is being allowed to keep coming until the high pressure rail is at 125 bar instead of the 85 bar it should be, at which point it is tripping into emergency shut down.
This bothers me some what as the high pressure regulator and the engine driven high pressure pump were both changed less than 10000 miles ago, if one bit is a low quality pattern part or even a counterfeit then it is highly likely so is the other.
On the plus side if the high pressure pump can push out 50% over pressure then a small drop in supply pressure caused by an in line fuel filter might not be detrimental. ( see post on fitting a fuel filter to a C5)