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 power switch is first turned to 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 | Power switch on (IG) → engine is started | A |
| Other than above | - | B |
| A | .gif) | CHECK FOR INTERMITTENT PROBLEMS |
|
.gif)
| 2. | CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM |
(a) Connect the Techstream to the DLC3.
(b) Turn the power 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 |
.gif)
|
| 3. | CHECK WHETHER DTC OUTPUT RECURS |
(a) Connect the Techstream to the DLC3.
(b) Turn the power 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 power 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 |
| B | | REPLACE COMBINATION METER ASSEMBLY |
READ NEXT:
Ignition Circuit
DESCRIPTION A direct ignition system is used on this vehicle. The direct ignition system is a 1 cylinder ignition system which ignites one cylinder with one ignition coil. In the 1 cylinder ignition s
Rough Idling
DESCRIPTION Problem Symptom Suspected Area Trouble Area
Engine speed fluctuation due to abnormal combustion
Idle speed too low or high
Strong engine vibration due to above symptoms
Rough Idling
DESCRIPTION Problem Symptom Suspected Area Trouble Area
Engine speed fluctuation due to abnormal combustion
Idle speed too low or high
Strong engine vibration due to above symptoms
SEE MORE:
Vehicle Speed Sensor "A" No Signal (P050031)
DESCRIPTION The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these wheel speed signals into a pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency
Control Module Communication Bus "B" Off Bus Off (U007488,...,U015187)
DESCRIPTION The skid control ECU (brake actuator assembly) communicates with the following ECUs and sensors via CAN communication.
ECM
TCM (ECM)
Yaw rate and acceleration sensor (airbag ECU assembly)
Steering angle sensor
Power steering ECU (rack and pinion power steering gear assembly)
