DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
CHECK ECM TERMINAL VOLTAGE (GREL TERMINAL)
INSPECT GLOW RELAY (GLOW 1 or 2)
INSPECT FUSE (GLOW 1 and GLOW 2)
INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)
CHECK GLOW PLUG ASSEMBLY (INSTALLATION)
CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY - GLOW PLUG - BATTERY AND BODY GROUND)
CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY - ECM AND BODY GROUND)
ECD SYSTEM (w/o DPF) - Pre-heating Control Circuit
DESCRIPTION
The glow plug is mounted inside the engine combustion chamber. To ensure efficient engine starting with a cold engine, the ECM calculates a time interval of the current that needs to flow through the glow plug depending on the starting engine coolant temperature when the ignition switch is turned to ON. The ECM then turns on the glow plug relay and permits current to flow through the glow plug based on the ECM calculated time. The glow plug is then heated, and enhances fuel combustion with a cold engine.
This DTC will be stored if the glow plug or the circuit is open.
These troubleshooting procedures are for: 1) difficult engine starting in cold weather, and 2) difficulty driving/vehicle malfunctions in cold weather immediately after engine is started.
After the engine is started, the ECM performs an "after-glow" for a certain period of time. In proportion to the actual engine coolant temperature, the time period varies. The after-glow reduces diesel engine knocking, white smoke emissions and engine noises when the engine is cold.
WIRING DIAGRAM
INSPECTION PROCEDURE
- After replacing the ECM, the new ECM needs registration () and initialization ().
| 1.CHECK ECM TERMINAL VOLTAGE (GREL TERMINAL) |
Remove the GLOW 1 relay from the engine room relay block.
Remove the GLOW 2 relay from the engine room relay block.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| GLOW 1 relay (2) - Body ground | Ignition switch ON | 11 to 14 V |
| GLOW 2 relay (2) - Body ground | Ignition switch ON | 11 to 14 V |
| 2.INSPECT GLOW RELAY (GLOW 1 or 2) |
Inspect the GLOW 1 relay ().
Inspect the GLOW 2 relay ().
| | REPLACE GLOW RELAY (GLOW 1 or 2) |
|
|
| 3.INSPECT FUSE (GLOW 1 and GLOW 2) |
Remove the GLOW 1 and GLOW 2 fuses from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Component | Condition | Specified Condition |
| GLOW 1 H-fuse | Always | Below 1 Ω |
| GLOW 2 H-fuse | Always | Below 1 Ω |
| | CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE |
|
|
| 4.INSPECT GLOW PLUG ASSEMBLY (RESISTANCE) |
Inspect the glow plug assembly ().
| | REPLACE GLOW PLUG ASSEMBLY ()
|
|
|
| 5.CHECK GLOW PLUG ASSEMBLY (INSTALLATION) |
Check the glow plug installation ().
- OK:
- Glow plugs are installed securely.
| 6.CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY - GLOW PLUG - BATTERY AND BODY GROUND) |
Remove the GLOW 1 relay from the engine room relay block.
Disconnect the C77 glow plug connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
No. 1| Tester Connection | Condition | Specified Condition |
| GLOW 1 relay (3) - C77-1 | Always | Below 1 Ω |
| GLOW 1 relay (5) - Positive (+) battery terminal cable | Always | Below 1 Ω |
| GLOW 1 relay (1) - Body ground | Always | Below 1 Ω |
Remove the GLOW 2 relay from the engine room relay block.
Disconnect the C78 glow plug connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
No. 2| Tester Connection | Condition | Specified Condition |
| GLOW 2 relay (3) - C78-1 | Always | Below 1 Ω |
| GLOW 2 relay (5) - Positive (+) battery terminal cable | Always | Below 1 Ω |
| GLOW 2 relay (1) - Body ground | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK | |
| |
| CHECK FOR INTERMITTENT PROBLEMS ()
|
|
| 7.CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY - ECM AND BODY GROUND) |
Remove the GLOW 1 relay from the engine room relay block.
Remove the GLOW 2 relay from the engine room relay block.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
for LHD| Tester Connection | Condition | Specified Condition |
| GLOW 1 relay (2) - C45-63 (GREL) | Always | Below 1 Ω |
| GLOW 2 relay (2) - C45-62 (GRL2) | Always | Below 1 Ω |
for RHD| Tester Connection | Condition | Specified Condition |
| GLOW 1 relay (2) - C46-63 (GREL) | Always | Below 1 Ω |
| GLOW 2 relay (2) - C46-62 (GRL2) | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
for LHD| Tester Connection | Condition | Specified Condition |
| GLOW 1 relay (2) or C45-63 (GREL) - Body ground | Always | 10 kΩ or higher |
| GLOW 2 relay (2) or C45-62 (GRL2) - Body ground | Always | 10 kΩ or higher |
for RHD| Tester Connection | Condition | Specified Condition |
| GLOW 1 relay (2) or C46-63 (GREL) - Body ground | Always | 10 kΩ or higher |
| GLOW 2 relay (2) or C46-62 (GRL2) - Body ground | Always | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
