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Hipo64
Hipo64, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3485
Experience:  Work and diagnose electronics on daily basis.
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Mercedes-Benz ML320 What causes the C1401 high pressure return

Resolved Question:

What causes the C1401 high pressure return pum code to come up on my 2002 ML 320? Lights on dash are on & it sounds like some or other pump is running blelow the windscreen washer bottle. Have had to disconnect the battery to get it turned off.

Submitted: 6 years ago.
Category: Mercedes
Expert:  Hipo64 replied 6 years ago.

Hipo64 :

This code is informing you for short or open circuit.

Hipo64 :

Hi and Welcome to just answer< I am Pavlin. I will do my best to help you.

Hipo64 :

click here

Hipo64 :

clcik here -left rear of engine compartment.

Customer:

So far I do not see your reply

Hipo64 :

the code you have is for shorted or open circuit to ABS control unit.

Hipo64 :

and that is why pump is working all the time

Hipo64 :

I am sending you info to trace circuits, this is the way to fix this problem

Customer:

What needs to be done to rectify the problem or does the pump have to be overhauled or replaced?

Hipo64 :

click on the first link I have sent to you please

Hipo64 :

there is the problematic circuit to be tested

Hipo64 :

it may be just wiring, or one of the units to be faulty

Hipo64 :

But wiring must be inspected first, as it may only be corroded wire or connector

Hipo64 and other Mercedes Specialists are ready to help you