Checking glow plugs Q10/Q14: VW 2.5 TDI (AXD, AXE, BLJ, BNZ, …)

Checking glow plugs
Q10
/
Q14
Special tools and workshop equipment required
Hand-held multimeter
V.A.G 1526 E
Auxiliary measuring set
V.A.G 1594C
Voltage tester
V.A.G 1527B
Vehicle diagnostic tester
Caution
Ceramic glow plugs are sensitive to knocks and bending. For this reason a glow plug which has dropped even just from a small height (approx. 2 cm) must not be used anymore. Even if no damage is apparent. It is absolutely necessary to follow the installation instructions, otherwise the heater pin of the glow plug can break and cause engine damage.
Transport and store only in original packaging or packed separately in bubble wrap.
Only remove ceramic glow plugs from their packaging immediately before installing them.
If there is any doubt as to the condition of the ceramic glow plugs, they should be renewed without exception.
Damaged ceramic glow plugs (e.g. heater pin of the glow plug is damaged) will invariably cause engine damage.
If the heater pin of the glow plug is damaged, the fragments must be removed from the combustion chamber before starting the engine for the first time, otherwise this will invariably cause mechanical damage.
Do not oil or grease thread of cylinder head bore or of ceramic glow plugs.
It is not permissible to install a combination of ceramic and metallic glow plugs.
Note
The glow plug system consists of the
automatic glow period control unit
J179
and the glow plugs.
The diagnosis of the
automatic glow period control unit
J179
is carried out using the
Vehicle diagnostic tester
. Any event memory entries are stored in the
engine control unit
J623
.
The
automatic glow period control unit
J179
detects any defective glow plugs.
In addition to the diagnosis via the
Vehicle diagnostic tester
, a continuity test can be performed on the glow plug in installed and removed condition.
Checking glow plugs in installed condition using
Vehicle diagnostic tester
:
Test prerequisites
Battery voltage at least 11.5 V
Fuse for glow plugs OK.
Automatic glow period control unit
J179
OK
Connect
Vehicle diagnostic tester
.
Switch ignition on.
Use
Guided fault finding
function to find any event memory entries concerning glow plugs stored in the
engine control unit
J623
.
Any event memory entries must be checked using the
Guided fault finding function
, and any faults must be rectified accordingly.
If there are no event memory entries, the glow plugs are OK.
In addition, a continuity test can be performed on the glow plugs.
Performing continuity test on installed glow plugs:
Note
When this test is performed, not all possible faults on the glow plugs can be detected.
Test prerequisites
Battery voltage at least 11.5 V
Ignition switched off
Fuse for glow plugs OK.
Automatic glow period control unit
J179
OK
Pull connectors off glow plugs.
Connect
voltage tester
V.A.G 1527B
cable to battery positive (+), using clips from
auxiliary measuring set
V.A.G 1594C
.
Place test probe of
voltage tester
V.A.G 1527B
on each glow plug one after the other.
If LED lights up: glow plug OK
If LED does not light up: fit new glow plug
Performing continuity test on removed glow plugs:
Connect wire of
hand-held multimeter
V.A.G 1526 E
to the glow plug to be tested using auxiliary clamps from
auxiliary measuring set
V.A.G 1594C
.
Fit test probe of
hand-held multimeter
V.A.G 1526 E
to earth connection of glow plug, and check continuity.
Repeat the test on all glow plugs one after the other.