Section 369 (Engine Immobilizer System - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2004 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.

Diagnosis System

Description
ECM controls the function of immobiliser on this vehicle.

Data of the immobiliser or Diagnostic Trouble Code (DTC) can be read from the Data Link Connector 3 (DLC3) of the vehicle. When a trouble occurs in immobiliser, Malfunction Indicator Lamp (MIL) does not light ON but DTC inspection is performed.

Therefore when there seems to be a trouble with immobiliser, use hand-held tester or SST (diagnosis check wire No. 2) to check and troubleshoot it.

Fig 1: Connecting Hand Held Tester To DLC3
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect the DLC3.

Fig 2: Identifying DLC3 Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

DLC3 CONNECTOR TERMINAL SPECIFIED CONDITION

Tester connection	Condition	Specified condition
7 (Bus (+) Line) - 5 (Signal Ground)	During communication	Pulse generation
4 (Chassis Ground) - Body Ground	Always	1 Ω or less
5 (Signal Ground) - Body Ground	Always	1 Ω or less
16 (B+) - Body Ground	Always	9 - 14 V

NOTE: If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or hand-held tester to the DLC3, turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool side.

If communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
If communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.

Inspect Diagnosis .
1. Using hand-held tester:
  Check the DTC.
  
  NOTE: The hand-held tester only:
  When the diagnosis system is switched from the normal mode to the check mode, it erases all DTCs and freezed frame data recorded in the normal mode. So before switching the modes, always check the DTCs and freezed frame data, and note them down.
  1. Prepare the OBD II scan tool (complying with SAE J 1978) or hand-held tester.
  2. Connect the OBD II scan tool or hand-held tester to the DLC3 under the instrument panel lower pad.
    
    Fig 3: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Turn the ignition switch ON and push the OBD II scan tool or hand-held tester switch ON.
  4. Use the OBD II scan tool or hand-held tester to check the DTCs and freeze frame data; note them down. (For operating instructions, see the OBD II scan tool's instruction book.)
  5. See DIAGNOSTIC TROUBLE CODE CHART to confirm the details of DTCs.
2. Using SST (diagnosis check wire No. 2):
  Check the DTC.
  1. Turn the ignition switch ON.
  2. Using SST, connect terminals 4 (CG) and 13 (TC) of the DLC3.
    SST 09843-18040
  3. Read the DTC from the MIL.
    NOTE:
    If a DTC is not output, check the TC terminal circuit.
    
    ECM controls the immobiliser function on this vehicle, DTC is output with DTC of engine.
    
    Fig 4: Connecting Terminals 4(CG) &13(TC) Of DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    As an example, the blinking patterns for codes; normal, 12 and 99 are as shown in the illustration.
    
    Fig 5: Identifying Blinking Patterns For Normal & Malfunction Codes
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. When DTC 99 is output, there is a trouble with immobiliser. Start troubleshooting referring to PROBLEM SYMPTOM TABLE.
  5. After completing the check, disconnect terminals 13 (TC) and 4 (CG) of the DLC3, and turn OFF the display.
  NOTE: If 2 or more malfunctions are found, the codes will be displayed from the smaller number to larger.
3. Clear the DTC.
  The following procedures will erase the DTCs and freeze frame data.
  1. Operating the OBD II scan tool (complying with SAE J1978) or hand-held tester to erase the codes. (See the OBD II scan tool's instruction book for operating instructions.)
  2. Disconnecting the battery terminals or EFI1 fuse.