Electro Hydraulic Power Assist Steering (EHPAS) On-Board Diagnosis
ELECTRO HYDRAULIC POWER ASSIST STEERING (EHPAS) ON-BOARD DIAGNOSIS
On-Board Diagnostic (OBD) Test Description
- The OBD test inspects the integrity and function of the EHPAS and outputs the results when requested by the specific tests.
- On-board diagnostic test also:
- Provides a quick inspection of the EHPAS usually performed at the start of each diagnostic procedure.
- Provides verification after repairs to ensure that no other faults occurred during service.
- The OBD test is divided into 2 tests:
- Read/clear diagnostic results, PID monitor and record.
Read/clear diagnostic results
- This function allows reading or clearing of DTCs in the EHPAS CM memory.
PID/Data monitor and record
- This function allows access of certain data values, input signals, calculated values, and system status information.
Reading DTCs Procedure
CMDTC self test
1. Connect the M-MDS (IDS) to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization screen of the IDS.
a. Select "Self Test".
b. Select "All CMDTCs".
3. Verify the DTC according to the directions on the screen.
- If any DTCs are displayed, perform troubleshooting according to the corresponding DTC inspection.
4. After completion of repairs, clear all DTCs stored in the EHPAS.
ODDTC self test
1. Connect the M-MDS (IDS) to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization screen of the IDS.
a. Select "Self Test".
b. Select "Modules".
c. Select "EPS".
3. Verify the DTC according to the directions on the screen.
- If any DTCs are displayed, perform troubleshooting according to the corresponding DTC inspection.
4. After completion of repairs, clear all DTCs stored in the EHPAS.
Clearing DTCs Procedure
CMDTC clearing procedure
1. Connect the M-MDS (IDS) to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization screen of the IDS.
a. Select "Self Test".
b. Select "All CMDTCs".
3. Verify the DTC according to the directions on the screen.
4. Press the clear button on the DTC screen to clear the DTC.
5. Switch the ignition OFF (LOCK).
6. Switch the ignition ON and wait for 5 s or more.
7. Perform DTC inspection.
8. Verify that no DTCs are displayed.
ODDTC clearing procedure
1. Connect the M-MDS (IDS) to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization screen of the IDS.
a. Select "Self Test".
b. Select "Modules".
c. Select "EPS".
3. Verify the DTC according to the directions on the screen.
4. Press the clear button on the DTC screen to clear the DTC.
5. Switch the ignition OFF (LOCK).
6. Switch the ignition ON and wait for 5 s or more.
7. Perform DTC inspection.
8. Verify that no DTCs are displayed.
PID/Data Monitor and Record Procedure
1. Connect the M-MDS (IDS) to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization screen of the IDS.
a. Select "DataLogger".
b. Select "Modules".
c. Select "EPS".
3. Select the applicable PID from the PID table.
4. Verify the PID data according to the directions on the screen.
NOTE:
- The PID data screen function is used for monitoring the calculated value of input/output signals in the module. Therefore, if the monitored value of the output parts is not within the specification, it is necessary to inspect the monitored value of input parts corresponding to the applicable output part control. In addition, because the system does not display an output part malfunction as an abnormality in the monitored value, it is necessary to inspect the output parts individually.
- When detecting DTCs, PIDs related to a malfunctioning system may not display even if the module is normal. Therefore, if a PID is not displayed, it is necessary to verify the DTC, perform malfunction diagnosis of the DTC that was detected, and do repairs.
DTC Table
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C: CMDTC self test, D: ODDTC self test
Fail-safe Function Table
PID/DATA Monitor Table
