P1155 Fault code

[Retali]

Hello once again,

Sadly after almost one year of peacefull relationship with my beloved Polo again i faced(last couple of months) the same fault codes i did ,
P1155 and P2279.

Usually first fault happens and then the air intake loss follows.

I read somewhere that when P1155 (SHORT TO B+ PLUS) occurs you have to check continuity.

Exactly the user writes "See if there is continuity between the B+ (check at the conn3ector) and the chassis ground. If there is, its shorted and trace the entire wiring back to the ECU."
How to i do that practically do that with a polymeter ?

I tried to check on youtube how to check continuity but there is nothing regarding map sensors and chassis ground.
If anyone can help with photos etc it would be appreciated.

PS: i switched the G71 map sensors to determine if it was the intake's G71's fault but the the faults keep coming up , so i guess its not a bad map sensor...unless both are kapputt (both OEM bought 2 years ago) .

[amer6R]

vw uses brown color wire for ground

if you mean with a multimeter?

disconnect the battery.
Put one lead in the brown pin of the connector ( or probe the wire from backside), put the other lead on the ground of the car ( metallic part like the engine) if you hear a beep then the ground is good. -if you don+t hear a beep than probably you have a break in the wire.
Also twist the connector ( move it a bit) to make sure the wires near it aren't corroded inside/ broken.


You can probe in similar way wires that ARE NOT meant to be connected - ( if you hear a beep and you know that they should not be connected then you have a Short)

[Retali]

vw uses brown color wire for ground

if you mean with a multimeter?

disconnect the battery.
Put one lead in the brown pin of the connector ( or probe the wire from backside), put the other lead on the ground of the car ( metallic part like the engine) if you hear a beep then the ground is good. -if you don+t hear a beep than probably you have a break in the wire.
Also twist the connector ( move it a bit) to make sure the wires near it aren't corroded inside/ broken.


You can probe in similar way wires that ARE NOT meant to be connected - ( if you hear a beep and you know that they should not be connected then you have a Short)

Yes, i meant with a multimeter.
Thanx a lot for the thorough directions !

Should i twist the connector while testing for continuity right ? (i mean it is self explanatory but i have to ask since i am a total noob to electrics)

Also can i check like this all the other 3 wires of the map sensors plug ?

1 year ago i have crimped the ecu's to map sensor cable with a new fuse, when the error reappeared i went to an electrician and asked him to check the crimps i have done, it came out 3 out of 4 were bad and did not have a good connection. I asked him to solder them. Which he did. But the faults came back the next hour. I was wondering if a map sensor go bad from bad wire connection of the fuse's wire... but both map sensors ?? i think its impossible.

Also i checked t he other fuse of the other G71 sensor that's near the throttle, and it appears the 4th cable has no rubber seal, whereas the other 3 do. I do not understand wtf happened with both of these fuses at some point.
Cause de facto the intake's one had no rubber seals at all.

[amer6R]

Like move it around, near the connector to be sure the wires arent rotted or damaged ( it happens sometimes).

You can wait for comments of more experienced members, they have more knowledge than me. For sure they will give you some nice tips.

[Retali]

Like move it around, near the connector to be sure the wires arent rotted or damaged ( it happens sometimes).

You can wait for comments of more experienced members, they have more knowledge than me. For sure they will give you some nice tips.

Thanx once again buddy. Your help is great.

So i did the test.

Cable 1 made a sound and the screen showed the number 10.
Cable 2 made no sound and showed the number 1
Cable 3 made NO sound BUT showed the number 160????
Cable 4 made no sound showed the number 1

Is something sorted ? Or are these measurements ok ?

[amer6R]

Cable 1 made a sound and the screen showed the number 10.
Cable 2 made no sound and showed the number 1
Cable 3 made NO sound BUT showed the number 160????
Cable 4 made no sound showed the number 1

Is something sorted ? Or are these measurements ok ?

I assume the cable one was brown ( ground). - And you put one lead onto the engine or metal part of the car.... ( GND)
-This means that your ground Cable is not broken

Cable 2,3,4 If one of your multimeter leads stayed still on the same place ( engine or metal part of the car (GND) this means that your cables 2, 3, 4 are not shorted to GND.

But you still can have possible shorts between cables 2, 3, 4. If we rule this out
And say that there are no additional sensors that share the same part of that harness then you can with 99% say that fault is in the Sensor.

Now there is probably a way to measure the resistance, of the sensor to confit its the cause and not the harness that is leading to it.

[Retali]

Cable 1 made a sound and the screen showed the number 10.
Cable 2 made no sound and showed the number 1
Cable 3 made NO sound BUT showed the number 160????
Cable 4 made no sound showed the number 1

Is something sorted ? Or are these measurements ok ?

I assume the cable one was brown ( ground). - And you put one lead onto the engine or metal part of the car.... ( GND)
-This means that your ground Cable is not broken

Cable 2,3,4 If one of your multimeter leads stayed still on the same place ( engine or metal part of the car (GND) this means that your cables 2, 3, 4 are not shorted to GND.

But you still can have possible shorts between cables 2, 3, 4. If we rule this out
And say that there are no additional sensors that share the same part of that harness then you can with 99% say that fault is in the Sensor.

Now there is probably a way to measure the resistance, of the sensor to confit its the cause and not the harness that is leading to it.

Goodmorning, yes i repeated the same procedure on all four cables and did the twisting aswell as you suggested.
Cable 1 was brown or black (i can not remember) , cable 2 is red, 3 is yellow and 4 is brown or black .

Now the thing is that i did the same test this morning on the second plug of the second identical G71 map sensor. And the measurements i got were , 1 beep, 2: 1 , 3: 1, 4: 1.

Does that mean that the yellow cable of the intake map sensor plug that gave the measurement of 176 (instead of 1 like the other identical plug) is broken ?

In order to help i attach a link that shows the plug (from jetta) also a wire diagram that iichel attached on the previous thread i had make.

https://workshop-manuals.com/volkswagen ... /page_826/

This is Polo 6R.

[amer6R]

you can test yellow cable in the same way as you tested the first cable, but you would have to probe it, or remove the conector on the other side.

I think the number you got is because probably some capacitors are in the circuit or diodes...

[Retali]

you can test yellow cable in the same way as you tested the first cable, but you would have to probe it, or remove the conector on the other side.

I think the number you got is because probably some capacitors are in the circuit or diodes...

Thanx brother, i will thoroughly check the yellow cable properly from ecu!