Hi,

I'm having an issue with my car and it's running really rough. OBD scanner gives me codes p0105 and p0110 as faulty codes. I've changed my MAP sensor and it didn't make any difference. My car is a Fiat Panda 169 2005.

Now I believe that the MAF sensor is what's causing the MAP to fail if I'm not wrong. But where is the MAF sensor located?

I've looked around the intake hoses and the only sensors along it are connected to the throttle body. One is the TPS sensor and other is MAF I think? I checked the voltage on it, it had two 11.55v connections and two ground. If that's the MAF sensor, how do I test it with a multimeter?

Only the Multijet Diesels have a MAF sensor and that will be located in the air intake truncking, in between the airbox and turbo.

The petrol models don't have them, but do have a MAP sensor plugged into the side of the throttle body.

What model have you got?

Have you any diagnostic kit?
Try logging what the airs doing (MAP and IAT?) both with Key on/engine off and engine running.

If you haven't got any scan tool, you might be able to check for a bad connection with the feed voltage to these sensors.

One of the wires to each sensor should probe 5v with the key on.

OBD scanner gives no reading on MAP sensor and voltage doesn't move when I test it with multimeter. What could that mean?

Understanding how sensors work will help.
Basically most sensors (except O2 sensors) take a reference voltage of 5 volts.
Alter is somehow.
Then return the altered signal voltage back to the PCM (engines ECU).
So most sensors will have 3 or 4 wires (4th usually ground)

There could be one or more of several faults and you need to work through them.

Break in the loom/connections for the reference signal voltage.

Break in loom/connections for the return signal voltage.

A short in the loom either voltage to ground.

Worth noting here that some models do have problems with the wiring loom from the PCM, some 1.1 Actives have had trouble with a broken wire in a Y joint, but it's usually ignition coil related.

The sensor itself (even though it's new or been swapped).

Another fault somewhere that makes this sensor's reading "unbelievable" by the PCM, for example an exhaust leak causing the O2 sensor to misread or a vacuum leak causing the MAP to misread.

Work through the possible solutions here
https://www.obd-codes.com/p0105

I have went through most of the steps but what's hindering me from going further is that the voltage on the MAP doesn't change when I accelerate. The wires around it are working fine. And I tried to check the voltage on the IAT sensor and it was going crazy when I accelerated. It was stable on Idle, but when I acclerated it went from -6v to +14v and was very unstable.

Rezgar said:

And I tried to check the voltage on the IAT sensor and it was going crazy when I accelerated. It was stable on Idle, but when I acclerated it went from -6v to +14v and was very unstable.

Click to expand...

Are you reading these signal via a scan tool or probing with a multimeter?

P0110 is a circuit malfunction of the IAT and not an IAT unexpectedly reading too high or too low. (P0113 & P0112)

From what I know, the IAT should read lower volts at higher temps and higher volts (closer to the reference 5v) at lower the temps.

https://www.obd-codes.com/p0110

As you've P0105 another circuit malfunction, this time of the MAP, I suspect some wiring or PCM issue. Perhaps the reference signal wire is shared/split and is broken or grounded.

Have you tried cleaning the PCM connectors, undo the two levered connectors on the PCM next to the battery, clean them up with contact cleaner, then trace the wire bunch, see if there's any damage to them.

Goudrons said:

Are you reading these signal via a scan tool or probing with a multimeter?

P0110 is a circuit malfunction of the IAT and not an IAT unexpectedly reading too high or too low. (P0113 & P0112)

From what I know, the IAT should read lower volts at higher temps and higher volts (closer to the reference 5v) at lower the temps.

https://www.obd-codes.com/p0110

As you've P0105 another circuit malfunction, this time of the MAP, I suspect some wiring or PCM issue. Perhaps the reference signal wire is shared/split and is broken or grounded.

Have you tried cleaning the PCM connectors, undo the two levered connectors on the PCM next to the battery, clean them up with contact cleaner, then trace the wire bunch, see if there's any damage to them.

Click to expand...

Yes I used a multimeter to test it. I doubt it was the IAT i was testing, it had 4 connections, two were 12v and two ground and it was attached to the throttle body next to the TPS.

Cleaning all the connectors with electronic spray was the first thing I did. Where is the PCM located? Tried looking at the car and looking online, but have no clue how the pcm looks or is placed. I suspected bad wiring myself but didn't know where to find the other end of the cables.

I have no clue where the IAT is located either, lack of info online and on my side. The faulty code for the IAT is relatively new, I think the rich condition of the car might have caused it. Because it's been running rich for a while now.

The PCM (engines ECU) is fixed to the left of the battery as you look under the bonnet.
It has two large, lever type connectors right on top of it.

As mentioned before, there have been issues with wires breaking in one of the bunches in one of the two looms from the PCM on 1.1's, though I've not heard of 1.2's having the same fault.


I think you'll need to connect up a scan tool and work out what these sensors are reading, I don't think you are getting anything meaningful by probing with a multimeter.

Most cheap bluetooth OBD2 code readers (see ebay) and the app Torque Pro (usually free with device or can be downloaded) for your smartphone/table should be enough to scan the sensors and turn off EML's.

Once you've pinpointed the effected sensor, then it's working out where it is, how to test it and how to test the wiring to it.

Don't forget, you've several signal's and places to test.
Reference signal needs testing at the sensors connector.
Is the sensor altering the signal (seen with a scan tool), return signal needs testing at the connector.
Is that altered signal getting back to the PCM, needs testing at the PCM connector.

I'm not sure all the sensors on the throttle body are replaceable.
I know the MAP is as I've swapped it out as a test before, but seem to think the rest are built in to the throttle body.

Rezgar said:

Yes I used a multimeter to test it. I doubt it was the IAT i was testing, it had 4 connections, two were 12v and two ground and it was attached to the throttle body next to the TPS.

Cleaning all the connectors with electronic spray was the first thing I did. Where is the PCM located? Tried looking at the car and looking online, but have no clue how the pcm looks or is placed. I suspected bad wiring myself but didn't know where to find the other end of the cables.

I have no clue where the IAT is located either, lack of info online and on my side. The faulty code for the IAT is relatively new, I think the rich condition of the car might have caused it. Because it's been running rich for a while now.

Click to expand...

I'm pretty sure the IAT function is performed by the MAP sensor. I've never had an IAT fault code logged by itself, and the one I did have disappeared when I replaced the MAP sensor, so I stopped looking for it.

Are you 100% sure the replacement MAP sensor is working properly? If it is a generic clone I would suspect it first, simply because it is almost impossible to tell if you have fixed your problems if the MAP is unreliable. MAP sensors do go bad, but it seems to be fairly rare. I reckon more get broken by people trying to clean them.

There are many on sale at a few quid, but I'm fairly sure that all the dodgy ones I have seen are all from the same source, despite different brand names on the packaging.

I would also re-clean the ECU connectors using a good quality Contact Cleaner. "Normal" WD40 is used by some, but it is not really the correct product, as it leaves a residue. They do make a WD40 Specialist Contact Cleaner, and it works very well for me. Procedure is: Disconnect Battery, Undo both ECU clips, remove both connectors, spray both male and female sides, leave to dry (ensure completely dry), re-attach connectors, reconnect battery.

Couple more questions for you

Where are you based?

Do you have anyone local with a Panda/Punto 1.2 8v who would be willing to let you try their MAP sensor?

Do you have a friendly breakers anywhere near you with a Panda/Punto 1.2 8v ready to break? If the engine can be run and tested first that will prove the MAP is OK. Borrow the MAP sensor and confirm it works or not on your car.

If it was me, I would get hold of a known working secondhand MAP sensor and try it before trying to find a possible wiring fault.

I'll do that. I'll disconnect the cables for the PCM and clean them. I used the lite version of Torque, maybe that's why it didn't give me a MAP reading.

No locals with Fat Panda, scarce here in Sweden. The scrap yard might have some.

The MAP sensor is a clone and it's making me doubt that it was working to begin with. Also the MAP doesn't change in signals when I use the multimeter, so it's not telling me anything. As if there's no vacuum inside the air system.

Rezgar - all the suggestions about finding another MAP are useful, if only to prove that the one on your car is working correctly, or not.

It's just a hunch, but I think you should try the car WITHOUT the crankcase breather connected to the airbox - just let the fumes vent to air for a few test miles. I had an issue where high crankcase pressure and a slight over-fill of oil caused too much hydrocarbons to get into the exhaust and it sent the lambda's all over the place. It threw very few lambda-related codes (although plenty of others), but once the vent went into a proper catch/vent tank instead of the engine, all was good again.

It's a free and easy check, that's all.

In that case wouldn't it be better to change the air filter that's inside the air case? I doubt it's safe to drive without the air case, because then debris would go into the engine.

So I removed the the connectors on the ECU and cleaned them, having the battery off the whole time. Once cleaned and dried, I put them back on as well as the battery. Then started car with MAP sensor and I get the same respsonce as before. No change. Connectors looked really dry and clean before I cleaned it.


These are the ECU connectors I assume.

View My Video
Here's the sound of the exhaust when the MAP sensor is on.

Here I plugged the MAP sensor on and you can listen to the engine, then plugged it off and it goes really quiet and stabilises.
View My Video

I noticed this loose cable, is it suppose to be attached to something? Never seen loose cables before, it's under the engine close to the MAP sensor and the throttle body.


I think the best option would be to find a scrap yard with my a car similar to mine and then test the MAP sensor on that one on mine. I'll make a few calls and see what I can find.

Rezgar said:

In that case wouldn't it be better to change the air filter that's inside the air case? I doubt it's safe to drive without the air case, because then debris would go into the engine.

Click to expand...

Ultimately, yes, but the point of my test is to remove the chance of crankcase fumes upsetting the lambda's - it's the one from the rocker-box cover into the air-box. Leave the airfilter in place for now, but of course check that it's not covered in oil, if the crankcase breather test proves successful.

The filter is dusty, I also saw some of that dust on top of the throttle. But it's not oily. Besides a new filter is like 10$.

Did this bad running suddenly start one day, or has it been a gradual worsening? Looking at your video, I would certainly change that MAP though.

I bought the car from a guy and drove it for one week. After that week a load of problems started appearing. Remembering now, the problem suddendly appeared and got worse over time. Did loads of tests and replaced few parts until I noticed that unplugging the MAP sensor was better than having it on.

But yea, it did appear without much notice. I think it started with the exhaust sounding a lot, then dark smoke coming out of it. And I think it was after that the engine started running rougher by time. When you accelerate and leave your foot off the gas it almost chokes. And at stops it has a hard time accelerating and could leave you with no acceleration.

I'd buy one of these;

https://www.shop4parts.co.uk/?name=store&op=Details&ProdID=14017&sku=268020

I'm sure they'll deliver to you quickly.

Yeah I know I have to get hold of a geniune MAP sensor to test on my car. However that one sure doesn't look geniuine, the real one is made by BOSCH.

I might go order one from the scrapyard that's fully functioning, should cost half of that, and you can return it with a 20% price reduction.