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ON-BOARD DIAGNOSTIC FUNCTION [DISCHARGE HEADLIGHT CONTROL MODULE]

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## Outline

• The on-board diagnostic function is incorporated into the discharge headlight control module (LH) and discharge headlight control module (RH). This function can narrow down discharge headlight malfunction locations.
• The on-board diagnostic function consists of the following functions: a failure detection function, which detects malfunctions in discharge headlight system-related parts; a memory function, which stores detected DTCs; a self-malfunction diagnostic function, which indicates system malfunctions using DTCs; and a PID/data monitoring function, which verifies the input/output condition of specific input/output signals being read out.
• Using an SST (WDS or equivalent), DTCs can be read out and deleted, and the PID/data monitoring function can be activated.

Block Diagram

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1 | Front combination light (LH)
2 | Front combination light (RH)
3 | Discharge headlight bulb (low-beam)
4 | Ignitor
5 | Discharge headlight control module (LH)
6 | Discharge headlight control module (RH)
7 | SST (WDS or equivalent)

## Self-Malfunction Diagnostic Function

• The self-malfunction diagnostic function determines that there is a malfunction, and outputs a signal, as a DTC, to the DLC-2. The DTC can be read out using an SST (WDS or equivalent).

## Failure Detection Function

• The failure detection function in each discharge headlight control module detects malfunctions in input/output signals.
• This function outputs the DTC for the detected malfunction to the DLC-2, and also sends the detected result to the memory function.

## Memory Function

• The memory function stores the DTC for the malfunction of input/output signals for related parts, as determined by the failure detection function.

DTC table

DTC | Description
--- | ---
B2386 | Discharge headlight illumination malfunction.
B2387 | Ignitor circuit malfunction.
B2388 | Discharge headlight operating voltage out of range.
B2389 | Discharge headlight illumination malfunction.
B2391 | Discharge headlight input resistance too high.
B2392 | Discharge headlight input voltage high.
B2393 | Discharge headlight control module output circuit malfunction.

## PID/Data Monitor Function

• The PID/data monitoring function optionally selects monitored input/output signal items that are set in the discharge headlight control module (LH) or the discharge headlight control module (RH), and performs read out in real time.
• An SST (WDS or equivalent) is used to read out the PID/data monitor information.

PID/Data monitor table (LHID)

PID name | Definition | Operation/unit (WDS or equivalent)
--- | --- | ---
CCNT | Number of continuous trouble codes | -
ONDEMDTC | Number of on-demand trouble codes | -
L_VOLT_L | Discharge headlight control (LH) input voltage | VOLTAGE
GDL_P_L | Output power to discharge headlight bulb (LH) | WATT
GDL_V_L | Output voltage to discharge headlight bulb (LH) | VOLTAGE

PID/Data monitor table (RHID)

PID name | Definition | Operation/unit (WDS or equivalent)
--- | --- | ---
CCNT | Number of continuous trouble codes | -
ONDEMDTC | Number of on-demand trouble codes | -
L_VOLT_R | Discharge headlight control module (RH) input voltage | VOLTAGE
GDL_P_R | Output power to discharge headlight bulb (RH) | WATT
GDL_V_R | Output voltage to discharge headlight bulb (RH) | VOLTAGE