Jaguar X-Type Sedan and Estate (Wagon). Manual — part 303

Published: 11-May-2011

Glow Plug System - Glow Plug System

Diagnosis and Testing

Principle of operation

As common rail diesel engines have better cold-starting characteristics than traditional diesel engines, the glow plugs have two functions on
this engine:

Pre-heat stage

In this stage, the glow plugs function as normal, preheating the combustion chambers to aid cold starting.

After-glow stage

At engine speeds below 2,500 rpm, and at temperatures below 50 degrees C (122 degrees F), the glow plugs continue to heat the cylinders
to improve idling and reduce emissions.

Warning light

The glow plug warning light on this vehicle not only informs the driver that the glow plugs are operating, but also as a malfunction indicator
lamp (MIL) for the engine management system. For additional information,
REFER to:

Glow Plug System

(303-07B Glow Plug System, Description and Operation).

Inspection and Verification

1. Verify the customer concern.

1.

2. Visually inspect for obvious signs of electrical damage.

2.

Electrical

Fuse 22, front power distribution box (60 Amp)
Fuse 18, front power distribution box (10 Amp)
Glow plug relay (R10, front power distribution box)
Engine management control relay (R7, front power distribution box)
W iring harness
Electrical connector(s)
Glow plug(s)
Engine control module (ECM)

CAUTION: W hen probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part number

3548-1358-00. Failure to follow this instruction may result in damage to the vehicle.

• NOTE: This section contains references to Parameter Identifiers (PIDs). Where the Jaguar approved diagnostic system is not available, a
scan tool may be used to access these PIDs, all of which give information, and some of which can be used to both read information and to
activate components. The format of the information may vary, depending on the tool used.

• NOTE: As well as carrying out its normal function the glow plug indicator also acts as an engine check lamp which will flash continuously
when a hard diagnostic trouble code (DTC) is detected by the ECM. Soft DTCs are also stored by the ECM but will only be identified if the
system is checked for DTCs using the Jaguar approved diagnostic system or a scan tool.

• NOTE: If a DTC is detected, all DTCs must be cleared after the concern is repaired. Failure to clear all DTCs may cause driveability
concerns.

• NOTE: When performing voltage or resistance tests, always use a digital multimeter (DMM) accurate to 3 decimal places, and with an
up-to-date calibration certificate. W hen testing resistance, always take the resistance of the DMM leads into account.

• NOTE: Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

• NOTE: If DTCs are recorded and the symptom is not present when performing the pinpoint tests, an intermittent concern may be the
cause. Always check for loose connections and corroded terminals.

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next

step.

3.

Diagnostic trouble code (DTC) index

DTC

Condition

Possible source

Action

P0380 Glow plug heater

circuit

Glow plug heater circuit: relay driver open circuit, short
circuit

For glow plug circuit tests, GO to Pinpoint
Test

A.

Pinpoint Tests

PINPOINT TEST A : GLOW PLUG CIRCUIT TESTS

TEST CONDITIONS

DETAILS/RESULTS/ACTIONS

A1: CHECK THE GLOW PLUG CIRCUIT(S) FOR SHORT CIRCUIT TO POWER

1
2
3
4

1
2

1

1
2

1

1
2
3
4

Engine control module (ECM) connector

Circuit

Pin

Glow plug - control

20

Glow plug relay connector

Circuit

Pin

Glow plug relay - control

02

Permanent 12 volt supply

03

ECM relay controlled 12 volt supply

01

Glow plug relay - output

05

Key off.
Glow plug fuse connector disconnected.
Key on, engine off.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug - control - Pin 02

Positive post

Is the resistance greater than 10 ohms?
Yes

GO to A3

.

No

GO to A2

.

A2: CHECK WHETHER THE SHORT CIRCUIT TO POWER IS IN THE HARNESS OR THE GLOW PLUGS

Glow plug assembly connector disconnected.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug - control - Pin 02

Positive post

Is the resistance greater than 10 ohms?
Yes

Harness is OK.Suspect :- Glow plug assembly.
REFER to:

Glow Plugs

(303-07B Glow Plug System, Removal and Installation).

No

REPAIR the short circuit. For additional information, refer to the wiring
diagrams.

A3: CHECK THE GLOW PLUG CIRCUIT CONTINUITY

Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug - control - Pin 02

Negative post

Is the resistance between 0.5 ohm - 10 ohms?
Yes

GO to A6

.

No

GO to A4

.

A4: CHECK THE GLOW PLUG CIRCUIT FOR SHORT CIRCUIT TO GROUND

Glow plug assembly connector disconnected.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug - control - Pin 02

Negative post

Is the resistance greater than 10 ohms?
Yes

GO to A5

.

No

REPAIR the short circuit. For additional information, refer to the wiring
diagrams.

A5: CHECK THE GLOW PLUG CIRCUIT(S) FOR OPEN CIRCUIT IN THE HARNESS

Measure the resistance between:

Glow plug relay connector

Glow plug relay connector

Glow plug - control - 15S-RD15 - Pin 01

Glow plug - control - Pin 02

Is the resistance less than 10 ohms?
Yes

Suspect:- Glow plug assembly
REFER to:

Glow Plugs

(303-07B Glow Plug System, Removal and Installation).

- Glow plug assembly GROUND

No

REPAIR the open circuit. For additional information, refer to the wiring
diagrams.

A6: CHECK THE GLOW PLUG CONTROL LINE 'ON' STATE

Scan tool connected.
Access and control the PID.
Activate the glow plugs.
Measure the voltage between:

Glow plug relay connector

Vehicle battery

Glow plug relay - output - Pin 01

Negative post

Is the voltage between 9 volts - 15 volts?
Yes

GO to A12

.

No

GO to A7

.

A7: CHECK THE GLOW PLUG CONTROL LINE FOR SHORT CIRCUIT TO GROUND

1
2
3
4

1

1

1
2
3
4

1

1
2
3
4

1
2
3
4

1

Key off.
Glow plug relay connector disconnected.
Key on, engine off.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - output - Pin 01

Negative post

Is the resistance greater than 10 ohms?
Yes

GO to A8

.

No

INSTALL a new front power distribution box assembly.

A8: CHECK THE GLOW PLUG CONTROL LINE FOR CONTINUITY

Measure the resistance between:

Glow plug relay connector

Glow plug relay connector

Glow plug relay - output - Pin 01

Glow plug relay - output - Pin 05

Is the resistance less than 10 ohms?
Yes

GO to A9

.

No

REPAIR the open circuit. For additional information, refer to the wiring
diagrams.

A9: CHECK SUPPLIES TO THE GLOW PLUG RELAY

Measure the voltage between:

Glow plug relay connector

Vehicle battery

ECM relay controlled 12 volt supply - Pin 01

Negative post

Permanent 12 volt supply - Pin 03

Negative post

Are the voltages between 9 volts - 15 volts?
Yes

GO to A10

.

No

No supply to the glow plug relay circuit. Check and repair the circuit as
necessary.

A10: CHECK THE ECM CONTROL LINE 'ON' STATE

Scan tool connected.
Access and control the glow plug control PID.
Activate the glow plugs.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Negative post

Is the resistance less than 10 ohms?
Yes

Suspect:- Glow plug relay connector- Glow plug relay fault

No

GO to A11

.

A11: CHECK THE ECM CONTROL LINE FOR SHORT CIRCUIT TO POWER

Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Positive post

Is the resistance greater than 10 ohms?
Yes

GO to A17

.

No

GO to A16

.

A12: CHECK THE GLOW PLUG CONTROL LINE 'OFF' STATE

Scan tool connected.
Access and control the glow plug control PID.
De-activate the glow plugs.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - output - Pin 01

Positive post

Is the resistance greater than 10 ohms?
Yes

An intermittent fault may be present in the wiring harness. Visually check for
chaffed wires or other physical damage to the harness. If no fault is found in
the circuit, suspect the following component(s):- Glow plug fuse connector-
Glow plug fuse fault

No

GO to A13

.

A13: CHECK THE GLOW PLUG CIRCUIT FOR SHORT CIRCUIT TO POWER IN THE HARNESS

Key off.
Glow plug relay connector disconnected.
Key on, engine off.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - output - Pin 01

Positive post

Is the resistance greater than 10 ohms?
Yes

GO to A14

.

No

INSTALL a new front power distribution box assembly.

A14: CHECK THE ECM CONTROL LINE FOR A SHORT CIRCUIT TO GROUND

Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Negative post

1
2
3
4

1
2
3
4

1
2
3

Is the resistance greater than 10 ohms?
Yes

Suspect :- Glow plug relay fault

No

GO to A15

.

A15: CHECK WHETHER THE SHORT CIRCUIT TO GROUND IS IN THE ECM HARNESS OR ECU

Key off.
ECM connector disconnected.
Key on, engine off.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Negative post

Is the resistance greater than 10 ohms?
Yes

Harness is OK.Suspect :- ECM fault

No

REPAIR the short circuit. For additional information, refer to the wiring
diagrams.

A16: CHECK WHETHER THE SHORT CIRCUIT TO POWER IS IN THE ECM HARNESS OR ECU

Key off.
ECM connector disconnected.
Key on, engine off.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Positive post

Is the resistance greater than 10 ohms?
Yes

Harness is OK.Suspect :- ECM fault

No

REPAIR the short circuit. For additional information, refer to the wiring
diagrams.

A17: CHECK THE ECM CONTROL LINE FOR CONTINUITY

Key off.
ECM connector disconnected.
Measure the resistance between:

Glow plug relay connector

Vehicle battery

Glow plug relay - control - Pin 02

Glow plug - control - Pin 20

Is the resistance less than 10 ohms?
Yes

Suspect :- ECM connector fault-ECM fault

No

REPAIR the open circuit. For additional information, refer to the wiring
diagrams.