Hi just had error code p26f700 come up 

Coolant pump "c" supply voltage circuit .

 

Car had been parked up a few weeks 

Took it for a spin and this popped up

The heater inside was never good .

So I changed the pump 

The one behind the sump rhs 

A gates model from the autofactors e130 ouch .

Started it up heater Working fine again .

But the code came back 

Checked the wiring the plug wasn't in great shape so I changed that 

Checked the negative and positive supply and it was fine .

 

Not sure how to test the yellow and green wire .

 

Any ideas ??

 

Options 

New pump might be faulty 

The other front pump might be faulty too 

The shroud on the main water pump is faulty " it's been changed with the timing belt a few weeks ago"

 

When you say checked the power and ground and they were fine, what do you mean?

 

What method was used?

what results were you expecting?

what results did you get?

In what state was the car when tested?

 

As it’s a voltage code I’d be looking more into this in detail.

 

The yellow/green wire is a LIN network back to the engine ecu.

I just tested it with a test light

And moved the loom checking for a break 

It remained constant 

Car was fine otherwise 

I hadn't driven it in 5 weeks or so .

 

Local mechanic said a faulty shroud on the water pump can throw up this code .

Although the management light can take a while to illuminate with the code reader the fault is straight away 

12 hours ago, working fool said:

I just tested it with a test light

And moved the loom checking for a break 

It remained constant 

Car was fine otherwise 

I hadn't driven it in 5 weeks or so .

 

Local mechanic said a faulty shroud on the water pump can throw up this code .

Although the management light can take a while to illuminate with the code reader the fault is straight away 

A test lamp is to be honest a terrible test, a bulb will light up at 6V and if LED will light up at 1.5V

 

You need a multi meter to test it properly to see true readings.

 

if you have high resistance due to corrosion or damaged wiring then a test lamp won’t help at all.

Well it was just a quick look before it's mot 

I'll test it more in the next few days 

Right an update 

 

Think I have it sorted .

Changed the pump for a gates pump 

Mil light still on 

Changed the plug and part of the loom 

Same problem .

Had the old plug and part of the wiring 

So tested the pumps I had .

Ended up with 4 

1 the original .ran for a second if tapped and stopped .

2 cheap ass ebay pump 20e 

Ran when it got power constantly .

3 a vw pump using the original part number .was surprisingly cheap 40e but came in an original vw box all part numbers were the same and made by pieberg 

When it got power ran for a few seconds and came back on every 5 or 6 seconds later .

4 .the autofactors new part 130e made by gates .same as the timing belt manufacturer. 

Gave it power noting at all.

Opened it up and spam the impeller with current still nothing 

Looks like it was a dud part .

Put the no3 pump on.

Ran the car for an hour 

Heater perfect 

Scanned the ecu and no codes at all