Now the car is playing up

[Brad93]

Only used to do this on long journeys on hot days. Today I’ve almost caused a pileup.

managed to get home ragging the crap out of it, driving on the starter motor

plugged in the gendan.

P0606 code - PCM/ECU FAULT

it’s a 2007 1.4 petrol polo.

Do I need a new ECU?

must be something to do with the heat, it only does it on hot days.

 

[The_Yellow_Ardvark]

Check the fuel air temp sensor and the temp sensor for the cooling.
A Passat I helped on had the same issue.
The temp sensor in the air inlet was failing.

 

[Brad93]

Check the fuel air temp sensor and the temp sensor for the cooling.
A Passat I helped on had the same issue.
The temp sensor in the air inlet was failing.

Could well be that, my gendan is saying air inlet temp is 45°

 

[Ruffian]

Could be a relay over heating cutting our power to the ecu.

If you know anyone with vcds (vagcom) get a scan done and will tell you further details into the fault code. (Ie voltage loss or signal)

 

[premmington]

Could be a relay over heating cutting our power to the ecu.

If you know anyone with vcds (vagcom) get a scan done and will tell you further details into the fault code. (Ie voltage loss or signal)

VCDS will give 16990/P0606/001542

VCDS may not give you freeze frame data - on an internal fault.

I would swap the relays - ignition and power hold relays are numbers 10 & 11 in the fuse box inside (facia)

Problem with these early Polos - unless the car has headlamp washers - there is no other relays in the box to swap about to prove the fault. There is just no other relays for highbeam/wipers/washer pumps that are the same. These are all micro switched from the BCM (body control module).


The only other way is to bridge the relay with a wire with two 1/4 lucar crimps on it - when it faults. Do one at a time when in a non start position - this will prove if it is the relays or not without spending money.

If you were in a non start position and got coms with your OBD reader - the ECU was live data wise - might be a better plan to look at live data - when in a non start position - see if any data is missing? Just because the ECU was live for coms does not mean it is live for function - ECU is fed up live thru PIN 9 from relay pack (interior fusebox).

Or did you plug it in - when it cooled down and the engine was running?


Not changed too many ECU's on these Polos - it has been all wiring faults and electric fuel pumps that has caused non starts that we have had in our workshop.

(All in all - I like a 1.4 16v Polo)

 

[Robbie260]

Hmmmmmmmm Mrk 4 golfs and that era passat and polos were famous for cooling water temperature sensors causing no end of bother if they went wrong. Another problems from cars of that age was the vacuum system pipe work or non return vavles going. Both causing the engine too idle badly and you having too rev the nuts off them too get them too go anywhere. Mass air flow sensors were another one that could cause similar problems. Lift the bonnet with the engine running and listen for a whistling noise that will indicate a vacuum leak.
Yours is a bit later but is of an age where these things could be starting too become a problem.

Doubt it be the ecu if it were that ******** even on an earlier car than yours the thing simply wouldnt start in the first place.

 

[Brad93]

What’s happening is, it will idle fine, I’ll go to pull way get to 10mph and it starts losing power, if you put your foot on the clutch it sometimes comes back, sometimes it just conks out.
It used to only happen pulling away.

Today it is losing all power at all speeds and all rev ranges, the revs start dropping off, battery light comes on, if you keep the foot on the gas it sometimes goes bang and like bump starts itself, for about 30 seconds then it happens again.

 

[Brad93]

It usually turns over and comes back to life, today it started being a right nob and not wanting to fire, but I did manage to get from Edmonton to Brentwood, with much drAma, but it always started.

 

[The_Yellow_Ardvark]

Back in the days of old, that would sound like "Carb Icing"

I have had it on a Renault 11. Bloody thing.

 

[jsf55]

Have you checked the battery output? didn't this happen last year too ?

 

[Ruffian]

Check the earth lead from the ns strut top to the battery. If in any doubt make a second earth strap to the gearbox bolt or similar.

 

[Brad93]

Have you checked the battery output? didn't this happen last year too ?

The battery is fine, I’ve done a few hundred feet on the battery/starter motor today.

Yes occurred last summer but nowhere near as bad

 

[premmington]

What’s happening is, it will idle fine, I’ll go to pull way get to 10mph and it starts losing power, if you put your foot on the clutch it sometimes comes back, sometimes it just conks out.
It used to only happen pulling away.

Today it is losing all power at all speeds and all rev ranges, the revs start dropping off, battery light comes on, if you keep the foot on the gas it sometimes goes bang and like bump starts itself, for about 30 seconds then it happens again.

What you are describing is the throttle body not opening the flap - air starvation against fuel load RPM.

It will idle OK - but you are losing throttle control.

Try spraying some carb cleaner down the throttle body. Clean it with a tooth brush or your finger.

 

[Ruffian]

@premmington

You probably know these engines also,
I'm trying to remember if these are the ones which carbon up the lower of the throttle body with the egr pipe. As that could play havoc also. I know it was the 1.4 in the lupo but cant remember if the polo was the same etc.

 

[Ashley Burton]

Yes VW have had problems with Throttle Bodies

Might be worth seeing if its sticking

 

[Mick Annick]

Youngest had a polo, died intermittently, traced to a chafed wire from the throttle going through the bulkhead - grommet failed

 

[premmington]

@premmington

You probably know these engines also,
I'm trying to remember if these are the ones which carbon up the lower of the throttle body with the egr pipe. As that could play havoc also. I know it was the 1.4 in the lupo but cant remember if the polo was the same etc.

I would guess it is a mechanical obstruction in the throttle body (carbon as you say).

If it was the motor or the postition sensor - it would throw a code.


Strange thou - Brad says it only does it when it is very hot?



I doubt thou it is the power hold relays - it would just die if the spark was cut - not loss of throttle control as he is explaining.


I replaced a throttle body on a 2011 Audi TT last week for doing the same thing (hot or cold). This one had lost its position sensor - you could see this on live data - also when tested on the bench with multimeter - the track was open circuit.

 

[Brad93]

I will take the TB off tomorrow if my mrs drops me at the workshop, if not it’s painting fences all day.

Ive been through similar things with various fiestas at this kinda mileage, 93,000.

ICV, MAF Sensors, Throttle Position sensors etc.

thanks for the ideas guys I will give them a check tomorrow, I just wanted to set fire to the thing today.

 

[500e]

Know a couple of people who can give instructions on last idea Brad

 

[premmington]

Know a couple of people who can give instructions on last idea Brad

That made me laugh - LOL