Lexus IS250 IS220d GSE20 ALE20 2AD-FHV ENGINE CONTROL SYSTEM
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT GLOW RELAY
INSPECT DIESEL GLW FUSE
INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)
CHECK GLOW PLUG ASSEMBLY (INSTALLATION)
CHECK HARNESS AND CONNECTOR (GLOW RELAY - ECM, GLOW RELAY - BODY GROUND)
CHECK HARNESS AND CONNECTOR (GLOW PLUG - GLOW RELAY, BATTERY - GLOW RELAY)
CHECK ECM TERMINAL VOLTAGE (GREL TERMINAL)
ECD SYSTEM - 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 engine switch is turned ON (IG). The ECM then turns on the GLOW relay and permits the current to flow through the glow plug based on the ECM's calculated time. The GLOW relay is then heated, and enhances fuel combustion with a cold engine.
This DTC will be set if the glow plug or the circuit is open.
These troubleshooting procedures are for: 1) difficult starting engine 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 .
Remove the GLOW relay from the engine room R/B.
Measure the resistance of the relay.
- Standard resistance:
| Tester Connection | Specified Condition |
| 3 - 5 | 10 kΩ or higher |
| 3 - 5 | Below 1 Ω
(when battery voltage is applied to terminals 1 and 2) |
| 2.INSPECT DIESEL GLW FUSE |
Remove the DIESEL GLW fuse from the engine room No. 1 R/B.
Measure the resistance of the fuse.
- Standard resistance:
- Below 1 Ω
| 3.INSPECT GLOW PLUG ASSEMBLY (RESISTANCE) |
Disconnect the glow plug wire.
Measure the resistance of the glow plugs.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| Glow plug terminal - Body ground | 20°C (68°F) | Approximately 0.95 Ω |
- If any of the glow plugs has an open circuit, the engine power will be insufficient only when the engine is cold.
Exercise extreme care not to damage the glow plug pipes. Damaging them could cause an open circuit, or shorten the life of the glow plugs.
Keep the glow plugs free of oil and fuel while cleaning.
Wipe any oil off of the terminal and Bakelite washer with a clean, dry cloth during inspection.
Do not apply more than 11 V to the glow plugs as it may cause an open circuit.
| | REPLACE GLOW PLUG ASSEMBLY |
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| 4.CHECK GLOW PLUG ASSEMBLY (INSTALLATION) |
Check the glow plug installation.
- OK:
- Glow plugs are installed securely.
- Torque:
- 13 N*m{
130 kgf*cm, 10 ft.*lbf}
| 5.CHECK HARNESS AND CONNECTOR (GLOW RELAY - ECM, GLOW RELAY - BODY GROUND) |
Disconnect the E59 ECM connector.
Measure the resistance of the wire harness side connectors.
- Standard resistance:
| Tester Connection | Specified Condition |
| GREL (E59-56) - R/B GLOW relay terminal 2 | Below 1 Ω |
| R/B GLOW relay terminal 1 - Body ground | Below 1 Ω |
| GREL (E59-56) - Body ground | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 6.CHECK HARNESS AND CONNECTOR (GLOW PLUG - GLOW RELAY, BATTERY - GLOW RELAY) |
Disconnect the A55 glow plug connector.
Measure the resistance of the wire harness side connectors.
- Standard resistance:
| Tester Connection | Specified Condition |
| R/B GLOW relay terminal 3 - Glow plug wire connector | Below 1 Ω |
| R/B GLOW relay terminal 5 - Positive (+) battery terminal cable | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 7.CHECK ECM TERMINAL VOLTAGE (GREL TERMINAL) |
Measure the voltage of the GLOW relay connector.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| 2 - 1 | Engine coolant temperature 40°C (104°F) or less | 9 to 14 V |
| OK | |
| |
| CHECK FOR INTERMITTENT PROBLEMS |
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