Ecd System Diagnosis System

  1. DESCRIPTION

  1. NORMAL MODE AND CHECK MODE

  1. 2-TRIP DETECTION LOGIC

  1. FREEZE FRAME DATA

  1. DLC3 (Data Link Connector 3)

  1. BATTERY VOLTAGE

  1. MIL (Malfunction Indicator Lamp)

Ecd System -- Diagnosis System



DESCRIPTION


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System.Ecd System Diagnosis System

  1. Description for M-OBD

    1. When troubleshooting Multiplex OBD (M-OBD) vehicles, the only difference from the usual troubleshooting procedure is to connect the GTS to the vehicle and read various data output from the vehicle's ECM.
    2. The vehicle's on-board computer illuminates the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in the computer itself or in drive system components. In addition to illuminating the MIL when a malfunction is detected, the applicable Diagnostic Trouble Codes (DTCs) are recorded in the ECM memory (LandCruiser RM000000VR600WX.html). When the malfunction does not reoccur, the MIL is illuminated until the ignition switch is turned off, and then the MIL is not illuminated when the ignition switch is turned ON but the DTCs remain recorded in the ECM memory.
    3. To check the DTC, connect the GTS to the Data Link Connector 3 (DLC3) on the vehicle or read the number of blinks of the MIL when the TC and CG terminals on the DLC3 are connected. The GTS also enables you to erase the DTCs, activate several actuators, check freeze frame data and various forms of engine data (for operating instructions, see the GTS instruction book).

NORMAL MODE AND CHECK MODE
The diagnosis system operates in the normal mode during normal vehicle use. It also has a check (test) mode for technicians to simulate malfunction symptoms and troubleshoot. Most DTCs use 2-trip detection logic to prevent an erroneous detection, and ensure a thorough malfunction detection. By switching the ECM to the check (test) mode using the GTS when troubleshooting, a technician can cause the MIL to light up for a malfunction that is only detected once or momentarily (GTS only) (See step 3).

2-TRIP DETECTION LOGIC
When a logic malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the same malfunction is detected again during the second drive test, this second detection causes the MIL to light up (2nd trip) (however, the ignition switch must be turned off between the 1st trip and 2nd trip).

FREEZE FRAME DATA
The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was moving or stationary, whether the engine was warmed up or not, as well as other data recorded at the time of a malfunction.

DLC3 (Data Link Connector 3)
The vehicle's ECM uses the ISO 14230 (M-OBD) communication protocol. The terminal arrangement of DLC3 complies with ISO 15031-03 and matches the ISO 14230 format.
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System.Ecd System Diagnosis System
HINT:
If the display shows a communication error message when the cable of the GTS is connected to the DLC3, the ignition switch is turned to ON, and the GTS is operated, there is a problem on either the vehicle side or the GTS side.
  1. If communication is normal when the GTS is connected to another vehicle, inspect the DLC3 on the original vehicle.
  2. If communication is impossible when the GTS is connected to another vehicle, the problem is probably in the GTS itself. Consult the Service Department listed in the GTS's operator's manual.

Symbol
Terminal No.
Name
Reference terminal
Result
Condition
CG
4
Chassis ground
Body ground
1 Ω or less
Always
SG
5
Signal ground
Body ground
1 Ω or less
Always
BAT
16
Battery positive
Body ground
11 to 14 V
Always
CANH
6
HIGH-level CAN bus line
14 - LOW-level CAN bus line
54 to 69 Ω
Ignition switch off
CANH
6
HIGH-level CAN bus line
16 - Battery Positive
1 MΩ or higher
Ignition switch off
CANH
6
HIGH-level CAN bus line
4 - Chassis ground
1 kΩ or higher
Ignition switch off
CANL
14
LOW-level CAN bus line
16 - Battery positive
1 MΩ or higher
Ignition switch off
CANL
14
LOW-level CAN bus line
4 - Chassis ground
1 kΩ or higher
Ignition switch off

BATTERY VOLTAGE
If the voltage is below 11 V, recharge the battery before proceeding.
Battery voltage:
11 to 14 V

MIL (Malfunction Indicator Lamp)

  1. The MIL illuminates when the ignition switch is on and the engine is not running.

    HINT:
    If the MIL is not illuminated, check the MIL circuit (refer to MIL Circuit (LandCruiser RM000000ZQY02CX.html)).

  2. The MIL should turn off when the engine is started. If the MIL remains illuminated, the diagnosis system will detect a malfunction or abnormality in the system.