Checking oil pressure and oil pressure switch for reduced oil pressure F378 — VW

Checking oil pressure and
oil pressure switch for reduced oil pressure
F378
Special tools and workshop equipment required
Oil pressure tester
V.A.G 1342
Voltage tester
V.A.G 1527 B
Auxiliary measuring set
V.A.G 1594 C
Jointed wrench 24 mm
T40175
Torque wrench
V.A.G 1331
(not illustrated)
Vehicle diagnostic tester
(not illustrated)
Prerequisites:
Engine oil level OK
Engine oil temperature at least 80 °C (radiator fan must have run once).
Note
Functional check and repair of optical and acoustic oil pressure display:
Current flow diagrams, Electrical fault finding and Fitting locations
and
Vehicle diagnostic tester
“Selection of functions and components”
.
Checking oil pressure
Only vehicles with sound generator: Open catch
1
, unclip fuel line
2
and loosen bolt
3
on activated charcoal filter. Place charge air pipe to one side.
Pull off breather line
1
, release activated charcoal filter
A
and remove upwards
B
. Lay activated charcoal filter to side.
Note
Place a cloth underneath bracket for ancillaries to catch any escaping engine oil.
Separate electrical connector
2
on
oil pressure switch for reduced oil pressure
F378
(brown).
Unscrew
oil pressure switch for reduced oil pressure
F378
1
.
Screw
oil pressure tester
V.A.G 1342
into oil filter bracket in place of oil pressure switch.
Screw
oil pressure switch for reduced oil pressure
F378
into
oil pressure tester
V.A.G 1342
.
Reconnect charge air pipe and breather line for activated charcoal filter.
Start engine.
Oil pressure at idling speed: 1.2 … 2.1 bar.
Oil pressure at 2000 rpm: 1.6 … 2.1 bar.
Oil pressure at 3700 rpm: 3.0…4.0 bar.
Note
During the first 1000 km the oil pressure could be 3.0 to 4.0 bar at 2000 rpm.
If specification is not attained:
Check strainer in oil intake pipe for dirt
Item
.
Check
valve for oil pressure control
N428
with
vehicle diagnostic tester
.
Note
Mechanical damage, e.g. to bearings, could also be the cause for oil pressure being too low.
If no fault is found:
Renew oil pump
Chapter
.
Check
oil pressure switch for reduced oil pressure
F378
(brown):
Stop engine.
Connect brown wire of tester to earth (-).
Connect
voltage tester
V.A.G 1527B
to battery positive (+) and
oil pressure switch for reduced oil pressure
F378
(brown) using cables from
auxiliary test set
V.A.G 1594C
.
LED must not light up.
If LED lights up, renew
oil pressure switch for reduced oil pressure
F378
.
If LED does not light up:
Start engine. At 0.55…0.85 bar, the LED must light up; otherwise renew oil pressure switch.
Checking
oil pressure switch
F22
(blue):
Stop engine.
Connect
voltage tester
V.A.G 1527B
to battery positive (+) and
oil pressure switch
F22
(blue) using cables from
auxiliary test set
V.A.G 1594C
.
LED must not light up.
If LED lights up, renew
oil pressure switch
F22
.
If LED does not light up:
Start engine and increase engine speed: At a pressure of 2.15 … 2.95 bar the LED must light up, otherwise renew oil pressure switch.