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Table of Contents > Repairing fuel supply (Passat, CC) > Checking fuel pump

VW Passat B6 Service Manual ➜ Checking fuel pump

CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
– Release electrical connectors -1 to 3- and pull them off. Then  
bend back locking lugs of connectors.  
Installing:  
– Connect connectors -1…3-. Observe colour co-ordination.  
– Check connectors are secured properly by pulling.  
– Insert fuel gauge sender - G- into guide on fuel delivery unit  
and press down until it engages.  
– Install fuel delivery unit ⇒ page 328 .  
7.3  
Checking fuel pump  
Note  
When replacing fuel delivery unit, check fuel tank for heavy soiling  
and clean if necessary.  
7. Repairing fuel supply (Passat, CC)  
331  
CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
Special tools and workshop  
equipment required  
♦ Pressure gauge - VAS 6550-  
♦ Remote control - V.A.G 1348/3A-  
♦ Test instrument adapter/DSO (5-pin) - VAS 5565-  
♦ Multimeter - V.A.G 1715-  
♦ Special wrench - T10202-  
♦ Measuring container, capacity at least 3 litres  
7.3.1  
Checking function and voltage supply  
Battery voltage at least 11.5 V.  
Fuse for fuel pump on fuse holder OK ⇒ Current flow diagrams,  
Electrical fault finding and Fitting locations.  
Fuel pump control unit - J538- OK.  
332  
Rep. gr.20 - Fuel supply system  
CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
Note  
Function of fuel pump is checked using final control diagnosis.  
If the final control diagnosis is to be carried out several times  
in succession, it may be necessary to start the engine briefly  
before repeating the final control diagnosis.  
– Connect vehicle diagnostic tester as follows:  
– Push diagnosis cable connector onto diagnosis connection in  
driver footwell.  
– Switch ignition on.  
– Press buttons on display one after the other for Vehicle  
self-diagnosis, Engine electronics and Final con-  
trol diagnosis.  
– Press right arrow button on display up to final control diag‐  
nosis for fuel pump electronics.  
The fuel pump must now run slowly up to maximum speed.  
Note  
The fuel pump runs very quietly.  
– Switch off ignition.  
If fuel pump does not run:  
– Remove bench seat ⇒ General body repairs, interior; Rep. gr.  
72 ; Removing and installing bench seat .  
– Pull connector off fuel pump control unit - J538- .  
– Check voltage supply between contacts -1- and -6- using mul‐  
timeter - V.A.G 1715- .  
Specification: approx. battery voltage  
Voltage supply not OK:  
– Locate and eliminate open circuit referring to current flow di‐  
agram ⇒ Current flow diagrams, Electrical fault finding and  
Fitting locations.  
Voltage supply OK:  
7. Repairing fuel supply (Passat, CC)  
333  
CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
– Remove cover -1- with fuel pump control unit - J538- -2- from  
fuel delivery unit.  
– First check that connector -A- is securely seated by pulling the  
connector without pressing the catch. If connector was not in‐  
serted correctly, repeat functional check of fuel pump.  
– Now pull off connector.  
– Check the contacts on the connector and on the fuel delivery  
unit for damage.  
WARNING  
Fuel supply line is pressurised. Wear protective goggles and  
protective clothing to avoid injury and contact with the skin.  
Wrap a cloth around the connection before loosening hose  
connections. Then release pressure by carefully pulling hose  
off connection.  
– Pull off fuel line -B- from the flange.  
Note  
Press in securing ring to release fuel line.  
On vehicles with auxiliary heater, the connector and the fuel  
line of the metering pump - V54- must also be disconnected.  
– Open locking ring using key - T10202- .  
Caution  
Do not cant key - T10202- and press against locking ring firmly.  
If the key slips off, the fuel delivery unit can be damaged.  
– Check that electrical wires between flange and fuel pump are  
connected.  
If no open circuit can be found:  
– Fuel pump defective, renew fuel delivery unit ⇒ page 326 .  
334  
Rep. gr.20 - Fuel supply system  
CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
7.3.2  
Checking fuel pressure  
Test conditions:  
Function of fuel pump has been checked ⇒ page 332 .  
Test sequence  
Note  
The fuel pressure must be checked by means of the final con‐  
trol diagnosis. If the fuel pressure is measured at idling speed,  
it may deviate from the specification.  
If the final control diagnosis is to be carried out several times  
in succession, it may be necessary to start the engine briefly  
before repeating the final control diagnosis.  
Note safety precautions before beginning work ⇒ page 278 .  
– Observe rules for cleanliness ⇒ page 280 .  
WARNING  
Fuel supply line is pressurised. Wear protective goggles and  
protective clothing to avoid injury and contact with the skin.  
Wrap a cloth around the connection before loosening hose  
connections. Then release pressure by carefully pulling hose  
off connection.  
– Pull off supply line (metal coupling) -arrow- and catch escaping  
fuel with a cloth.  
Note  
Press in securing ring to release fuel line.  
7. Repairing fuel supply (Passat, CC)  
335  
CC 2010 ➤ , Eos 2006 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Passat 2006 ➤ , ...  
4-cyl. injection engine (1.8 and 2.0 l engine, chain drive) - Edition 08.2018  
– Connect pressure tester - VAS 6550- to fuel supply line with  
adapter - VAS 6550/1- and -VAS 6550/2- .  
– Make sure that drain tap is closed and cut-off taps are open.  
– Actuate fuel pump with final control diagnosis to build up fuel  
pressure.  
– Read fuel pressure on pressure gauge.  
Specification: 4.0 to 7.0 bar  
If fuel pressure is OK, check holding pressure ⇒ page 338 .  
If the specification is exceeded:  
– Pressure limiting valve in flange defective, renew flange with  
fuel filter ⇒ Item 15 (page 282) .  
If specification is not obtained  
– Check fuel lines for possible restrictions (kinks) or blockages.  
If no fault is found:  
– Renew flange with fuel filter and pressure limiting valve  
⇒ Item 15 (page 282) .  
– Repeat check.  
If reading again does not match specification:  
– Fuel pump defective, renew fuel delivery unit ⇒ page 326 .  
7.3.3  
Checking fuel pressure when the engine  
is running (engine codes CCZA, CCZB,  
CDAA, CDAB)  
Note  
If a complaint is made about the vehicle's performance, the  
reason may be that the fuel pressure is too low. Faults in the  
high-pressure section may also be caused by inadequate fuel  
pressure in the low-pressure section. This check determines  
the fuel pressure in the high-pressure and low-pressure sec‐  
tions during a road test. Fuel pressure in the high-pressure  
section is read from the engine control unit. The lowest fuel  
pressure is measured by the pressure tester - VAS 6550- and  
reported to the vehicle diagnosis and service information sys‐  
tem - VAS 5052 B- .  
This test can be part of “Guided Fault Finding” if an entry has  
been made in the event memory. However, it can also be star‐  
ted in the vehicle diagnosis and service information system -  
VAS 5052 B- by means of “Functions and component  
selection”.  
Special tools and workshop equipment required  
♦ Pressure gauge - VAS 6550-  
♦ Hose adapters - VAS 6550/1- and -VAS 6550/2-  
♦ Vehicle diagnosis and service information system - VAS 5052  
B-  
♦ Connector cable - VAS 5051/66-  
– Remove bench seat ⇒ General body repairs, interior; Rep. gr.  
72 ; Removing and installing bench seat .  
336  
Rep. gr.20 - Fuel supply system