Toyota CH-R Service Manual: Diagnosis System

DIAGNOSIS SYSTEM

OBD II (w/ Canister Pump Module)

(a) When troubleshooting OBD II (On-Board Diagnostics) vehicles, an OBD II scan tool (complying with SAE J1978) must be connected to the DLC3 (Data Link Connector 3) of the vehicle. Various data in the vehicle ECM (Engine Control Module) can be then read.

(b) OBD II regulations require that the vehicle on-board computer illuminate the MIL (Malfunction Indicator Lamp) on the instrument panel when the computer detects a malfunction in:

(1) The emission control system components.

(2) The powertrain control components (which affect vehicle emissions).

(3) The computer itself.

In addition, the applicable DTCs prescribed by SAE J2012 are recorded in the ECM memory. If the malfunction does not recur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the ECM memory.

(c) To check for DTCs, connect the Techstream to the DLC3. The Techstream displays DTCs, freeze frame data, and a variety of engine data. The DTCs and freeze frame data can be cleared with the Techstream. In order to enhance OBD function on vehicles and develop the off-board diagnosis system, Controller Area Network (CAN) communication is used in this system. CAN is a network which uses a pair of data transmission lines spanning multiple computers and sensors. It allows for high speed communications between the systems and simplification of the wire harness connections.

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EURO-OBD (w/o Canister Pump Module)

(a) When troubleshooting Europe On-Board Diagnostic (Euro-OBD) vehicles, the vehicle must be connected to an OBD scan tool (complying with ISO 15765-4). Various data output from the vehicle ECM can then be read.

(b) Euro-OBD regulations require that the vehicle on-board computer illuminate the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in any of the following:

(1) The emission control system/components

(2) The powertrain control components (which affect vehicle emissions)

(3) The computer

In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15765-4 are recorded in the ECM memory.

If the malfunction does not recur in 3 consecutive trips, the MIL goes off automatically but the DTCs remain recorded in the ECM memory.

(c) To check DTCs, connect the Techstream or OBD scan tool to the Data Link Connector 3 (DLC3) of the vehicle. The scan tool displays DTCs, freeze frame data and a variety of engine data.

The DTCs and freeze frame data can be cleared with the scan tool.

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NORMAL MODE AND CHECK MODE

(a) Techstream only:

The diagnosis system operates in normal mode during normal vehicle use. In normal mode, 2 trip detection logic is used to ensure accurate detection of malfunctions. Check mode is also available as an option for technicians. In check mode, 1 trip detection logic is used for duplicating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent problems.

2 TRIP DETECTION LOGIC

(a) When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the same malfunction is detected during the subsequent driving cycle, the MIL is illuminated (2nd trip).

FREEZE FRAME DATA

(a) 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 and whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

(b) The Techstream displays freeze frame data recorded at five different points: 1) 3 times before the DTC is stored, 2) once when the DTC is stored, and 3) once after the DTC is stored. The data can be used to reproduce the vehicle condition around the time of the malfunction. The data may be helpful in determining the cause of a malfunction. It may also be helpful in determining whether a DTC is being caused by a temporary malfunction.

LIST OF FREEZE FRAME DATA

CHECK DATA LINK CONNECTOR 3 (DLC3)

(a) Check the DLC3.

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CHECK BATTERY VOLTAGE

Standard voltage:

11 to 14 V

If voltage is below 11 V, replace or recharge the battery before proceeding to the next step.

MIL (Malfunction Indicator Lamp)

(a) Check that the MIL illuminates when the ignition switch is turned to ON.

If the MIL does not illuminate, there is a problem in the MIL circuit.

(b) When the engine is started, the MIL goes off.