Lexus ES: MIL Circuit
DESCRIPTION
The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM.
The MIL operation can be checked visually. When the engine switch is first turned on (IG), the MIL should be illuminated and should then turn off after the engine is started. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.
WIRING DIAGRAM
PROCEDURE
| 1. | CHECK THAT MIL IS ILLUMINATED |
(a) Perform troubleshooting in accordance with the table below.
| MIL | Condition | Proceed to |
|---|---|---|
| Illuminates → Turns off | Engine switch on (IG) → engine is started | A |
| Other than above | - | B |
| A | .gif) | CHECK FOR INTERMITTENT PROBLEMS |
|
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| 2. | CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Check the communication between the Techstream and ECM.
HINT:
It can be checked using the "Engine" item of the Data List.
| Result | Proceed to |
|---|---|
| Communication is possible | A |
| Communication is not possible | B |
| B | | GO TO VC OUTPUT CIRCUIT |
|
| 3. | CHECK WHETHER DTC OUTPUT RECURS |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: System Select / Health Check.
(e) Check if any DTCs have been detected. Note down any DTCs.
| Result | Proceed to |
|---|---|
| DTCs are not output | A |
| Any DTCs is output | B |
HINT:
Check for detected DTCs output from other ECUs which relate to the MIL.
| B | | REPAIR CIRCUIT INDICATED BY OUTPUT |
|
| 4. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Combination Meter / Active Test / Check Engine Warning.
Body Electrical > Combination Meter > Active Test| Tester Display |
|---|
| Check Engine Warning |
(e) Check the status of the MIL while performing the Active Test.
| Result | Proceed to |
|---|---|
| Changes | A |
| Does not change | B |
| A | | REPLACE ECM |
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| B | | REPLACE COMBINATION METER ASSEMBLY |
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Rough Idling
DESCRIPTION Problem Symptom Suspected Area Trouble Area
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Idle speed too low or high
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INSPECTION PROCEDURE 1. INSPECT OIL PUMP RELIEF VALVE (a) Coat the oil pump relief valve with engine oil and check that it falls smoothly into the valve hole by its own weight. HINT: If the oil pump relief valve does not fall smoothly, replace the timing chain cover assembly. 2. INSPE
Outside Vehicle
OUTSIDE VEHICLE
These are maintenance and inspection items that are considered to be
the owner's responsibility.
The owner can do them or they can have them done at a service center.
These items include those that should be checked on a daily basis, those
that in most cases
