PROCEDURE
| CAUTION | The power steering control module continues to operate after the engine stops and calculate the temperature in the control module. Therefore, before starting service of the power steering system which requires disconnection of the connector, stop the engine and allow approx. 10 minutes until the control module becomes cold. Before removal or installation, be sure to remove any foreign matter (dust, moisture, oil, etc.) from the power steering control module connector. |
Note. Shake the connector at the suspected trouble location to check for open or short circuits of the harness. Refer to "Check List for Interview". < Refer to CHECK LIST FOR INTERVIEW . >
| Step | Check | Yes | No |
|---|---|---|---|
| 1 CHECK PRE-INSPECTION. Ask the customer when and how the trouble occurred using the interview check list. < Refer to CHECK LIST FOR INTERVIEW . > Check the illumination status of the steering warning light while the engine is running. Before performing diagnostics, check components which might affect power steering problems. < Refer to INSPECTION , General Description. > Save the data of «Overheating protection intervention history» «IGN count from overheating protection (most recent) (previous) (before previous)» «Assist limit history (low voltage, high voltage)» using Subaru Select Monitor. < Refer to READ CURRENT DATA , OPERATION, Subaru Select Monitor. > | Are components that might influence the power steering problem operating properly? | Go to step 2 . | Repair or replace each component. |
| 2 CHECK INDICATION OF DTC. Turn the ignition switch to OFF. Connect the Subaru Select Monitor to data link connector. Turn the ignition switch to ON and run the Subaru Select Monitor. Read the DTC using the Subaru Select Monitor. < Refer to OPERATION , Read Diagnostic Trouble Code (DTC). > NOTE: If the communication function of the Subaru Select Monitor cannot be executed properly, check the communication circuit. < Refer to COMMUNICATION FOR INITIALIZING IMPOSSIBLE , INSPECTION, Subaru Select Monitor. > | Is DTC displayed? | Record the DTC. Go to step 4 . | Go to step 3 . |
| 3 PERFORM GENERAL DIAGNOSTICS. If the steering warning light is illuminated while the engine is running, perform the Clear Memory Mode. < Refer to OPERATION , Clear Memory Mode. > Perform the Inspection Mode. < Refer to INSPECTION MODE . > Read the DTC. < Refer to OPERATION , Read Diagnostic Trouble Code (DTC). > Check the DTC is not displayed. | Does the steering warning light illuminate at ignition switch ON, and turn off two seconds after the engine is started? | Finish the diagnosis. | < Refer to WITHOUT DTC , INSPECTION, Subaru Select Monitor. > |
| 4 CHECK FREEZE FRAME DATA. Using the Subaru Select Monitor, check the freeze frame data for the power steering control module. | Are freeze frame data recorded? | Record the freeze frame data. Go to step 5 . | Go to step 5 . |
| 5 PERFORM DIAGNOSIS. Refer to "List of Diagnostic Trouble Code (DTC)". < Refer to LIST , List of Diagnostic Trouble Code (DTC). > Correct the cause of trouble. Check the illumination status of the steering warning light while the engine is running, and if the warning light is lit, perform Clear Memory Mode. < Refer to OPERATION , Clear Memory Mode. > Perform the Inspection Mode. < Refer to INSPECTION MODE . > Read the DTC. < Refer to OPERATION , Read Diagnostic Trouble Code (DTC). > | Is DTC displayed? | Repeat step 5 until DTC is not shown. | Finish the diagnosis. |
| NOTE |
|---|
| If the communication function of the Subaru Select Monitor cannot be executed properly, check the communication circuit. < Refer to COMMUNICATION FOR INITIALIZING IMPOSSIBLE , INSPECTION, Subaru Select Monitor. > |
CHECK
Check the following items regarding condition of the vehicle.
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SRS AIRBAG SYSTEM
The airbag system wiring harness is routed near the power steering control module.
| CAUTION | Do not use the electrical test equipment on the airbag system wiring harnesses or connector circuits. Be careful not to damage the airbag system wiring harness during maintenance of the power steering control module. |
BATTERY
Measure the battery voltage and check electrolyte.
Standard voltage: 12 V or higher (must not drop below 10 V during operation under electrical load)
Specific gravity: 1.260 or more
TIRES
Check the tire specifications, tire wear and air pressure. < Refer to SPECIFICATION , General Description. >
GENERAL TOOL
| TOOL NAME | REMARKS |
|---|---|
| Circuit tester | Used for measuring resistance, voltage and current. |
| Oscilloscope | Used for measuring the sensor. |
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Note. The terminal numbers of the power steering control module connectors are as indicated in the figure.
| Description | Terminal No. | Input/output signal |
|---|---|---|
| Measured value and measuring conditions | ||
| Power supply (IG SW) | A1 | Battery voltage is detected with the ignition switch ON when measuring between A1 - B1. |
| Subaru Select Monitor communication line | A2 | Digital signal; can not be measured |
| Shield GND | A3 | 0 V is constantly detected. |
| Main torque sensor | A4 | The voltage changes when the steering is operated to the right or left with the ignition switch ON. |
| Sub torque sensor | A5 | The voltage changes when the steering is operated to the right or left with the ignition switch ON. |
| CAN communication | A6 | Digital signal; can not be measured |
| CAN communication | A7 | Digital signal; can not be measured |
| Torque sensor operating power supply | A8 | Approximately 8 V is detected with ignition switch ON. |
| Torque sensor ground | A9 | 0 V is constantly detected. |
| Torque sensor standard power supply | A10 | Approximately 3 V is detected with ignition switch ON. |
| Ground | B1 | Battery voltage is constantly detected when measuring between B1 - B2. |
| Power supply | B2 | |
| Resolver S1 | C1 | Varies depending on the operational status of the motor. |
| Resolver S3 | C2 | |
| Resolver S2 | C3 | |
| Resolver S4 | C4 | |
| Excitation power supply for resolver | C5 | |
| Common output | C6 | |
| Motor U phase | D1 | Varies depending on the motor output. |
| Motor V phase | D2 | |
| Motor W phase | D3 |
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- Prepare the Subaru Select Monitor kit. < Refer to «SPECIAL TOOL»(ref-560391-S01873193722013061300000) , PREPARATION TOOL, General Description. >
- Prepare PC with Subaru Select Monitor installed.
- Connect the USB cable to SDI (Subaru Diagnosis Interface) and USB port on the personal computer (dedicated port for the Subaru Select Monitor). NOTE: The dedicated port for the Subaru Select Monitor means the USB port which was used to install the Subaru Select Monitor.
- Connect the diagnosis cable to SDI.
- Connect SDI to data link connector located in the lower portion of the instrument panel (on the driver's side). CAUTION: Do not connect scan tools other than the Subaru Select Monitor.
- Start the PC.
- Turn the ignition switch to ON (engine OFF) and run the "PC application for Subaru Select Monitor".
- Record the DTC and data. NOTE: For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".
- If the power steering control module and Subaru Select Monitor can not communicate, check the communication circuit. < Refer to «COMMUNICATION FOR INITIALIZING IMPOSSIBLE»(ref-560391-S02806349322013061300000) , INSPECTION, Subaru Select Monitor. >
READ CURRENT DATA
- On «Main Menu» display, select {Each System Check}.
- On «System Selection Menu» display, select {Power Steering System}.
- On «Power Steering Diagnosis» display, select {Current Data Display & Save}.
- Using the scroll key, scroll the display screen up or down until the desired data is shown.
The list is indicated in the following table.
| Display | Contents to be displayed | Range | Unit |
|---|---|---|---|
| Torque sensor main output | Main torque sensor output voltage is displayed. | 0 - 5 | V |
| Torque sensor sub output | Sub torque sensor output voltage is displayed. | 0 - 5 | V |
| Torque sensor reference voltage | Torque sensor standard voltage is displayed. | 0 - 5 | V |
| Power current | The current flowing to CM is displayed. | 128 - 127 | A |
| Vehicle speed | Vehicle speed is displayed. (CAN communication data) | 0 - 255 | Km/h |
| Engine speed | Engine speed is displayed. (CAN communication data) | 0 - 12750 | Rpm |
| Detection current at ECM | The current flowing to the motor relay is displayed. | 128 - 127 | A |
| 3-phase motor current (U-phase) | The U phase actual current value as calculated by the microcomputer from the torque sensor input is displayed. | 128 - 127 | A |
| 3-phase motor current (V-phase) | The V phase actual current value as calculated by the microcomputer from the torque sensor input is displayed. | 128 - 127 | A |
| Motor angular speed | Data from the resolver sensor is displayed. | 4096 - 4064 | Rpm |
| ECM Temperature | The thermistor temperature of the steering control module is displayed. | 50 - 205 | °C |
| Power supply voltage | Battery voltage is displayed. | 0 - 25.5 | V |
| Torque sensor power supply voltage | The power supply voltage output to the torque sensor is displayed. | 0 - 10.2 | V |
| IG voltage | The power supply voltage supplied to the ECM is displayed. | 0 - 25.5 | V |
| CAN bus status | Either Active/Passive/Bus Off is displayed. | Active | |
| EPS operating condition | Either Normal/Assist Stop/Assist Limitation is displayed. | Normal | |
| Target Current at ECM | The motor target current value required for assist is displayed. | 128 - 127 | A |
| Steering angle | Steering angle of steering wheel is displayed. | 640 - 635 | Deg |
| Reading assist MAP | Either MAP1/MAP2/MAP3 is displayed. | MAP1 | |
| Overheating protection intervention history | Number of interventions to the overheat protection control (assist limitation for protecting the power steering from overheating) (1) | 0 - 250 | Times |
| IGN count from overheating protection (most recent) | Number of times the ignition switch is ON from the intervention to overheat protection control (most recent) until now (2) | 0 - 65000 | Times |
| IGN count from overheating protection (previous) | Number of times the ignition switch is ON from the intervention to overheat protection control (previous) until now (2) | 0 - 65000 | Times |
| IGN count from overheating protection (before previous) | Number of times the ignition switch is ON from the intervention to overheat protection control (before previous) until now (2) | 0 - 65000 | Times |
| Assist limit history (low voltage, high voltage) | Number of intervention to assist limit when the power supply voltage is low or high (1) | 0 - 250 | Times |
| (1) When the value exceeds the maximum of 250 times, 250 is displayed. (2) When there is no intervention of the overheating protection control, "65535" is displayed. If an error such as control unit memory error, etc. occurs, "65534" is displayed. | |||
| (1) | When the value exceeds the maximum of 250 times, 250 is displayed. |
| (2) | When there is no intervention of the overheating protection control, "65535" is displayed. If an error such as control unit memory error, etc. occurs, "65534" is displayed. |
FREEZE FRAME DATA
Note. Freeze frame data stored at the time of trouble occurrence is shown on the display. Each time a trouble occurs, the latest information is stored in the freeze frame data in memory. One freeze frame data will be stored.
DETECTING CONDITION
- Defective harness connector
- Defective power steering control module
- Defective combination meter
- Open circuit of harness
Reproduce the malfunction occurrence condition as much as possible.
- Defective combination meter
- Defective harness
CAN communication error (Engine rpm signal not received)
- Defective combination meter
- Open circuit of harness
LIST
| DTC | Item | Content of diagnosis | Note |
|---|---|---|---|
| None | Without DTC | Normal | < Refer to WITHOUT DTC , INSPECTION, Subaru Select Monitor. > |
| "Assist limitation" is displayed in the current data «EPS operating condition». | Assist limitation is performed due to overheat protection control. | < Refer to POWER STEERING ASSIST DISABLED , STEERING WARNING LIGHT DOES NOT COME ON, STEERING Warning Light. > | |
| The current data «Overheating protection intervention history» is more than once. | There are previous records of intervention to overheat protection control. | < Refer to POWER STEERING ASSIST DISABLED , STEERING WARNING LIGHT DOES NOT COME ON, STEERING Warning Light. > | |
| C2511 | Torque Sensor Failure 1 (Main) | Poor connector contact Forgot to connect connector Faulty torque sensor section circuit Faulty torque sensor coil | < Refer to DTC C2511 TORQUE SENSOR FAILURE 1 (MAIN) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2512 | Torque Sensor Failure 2 (Sub) | < Refer to DTC C2512 TORQUE SENSOR FAILURE 2 (SUB) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > | |
| C2513 | Torque Sensor Failure 3 (Much Tolerance) | < Refer to DTC C2513 TORQUE SENSOR FAILURE 3 (MUCH TOLERANCE) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > | |
| C2514 | Torque Sensor Power Supply Failure | < Refer to DTC C2514 TORQUE SENSOR POWER SUPPLY FAILURE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > | |
| C2521 | Motor Failure 1 (Motor) | Poor connector contact Forgot to connect connector Harness open/short circuit Motor open circuit Power transistor shorted/open Terminal power supply or ground short | < Refer to DTC C2521 MOTOR FAILURE 1 (MOTOR) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2522 | Motor Failure 2 (Angle Abnormal) | < Refer to DTC C2522 MOTOR FAILURE 2 (ANGLE ABNORMAL) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > | |
| C2531 | ECU Failure 1 (CPU Failure) | Faulty main unit of power steering control module | < Refer to DTC C2531 ECU FAILURE 1 (CPU FAILURE) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2532 | ECU Failure 2 (Peripheral Circuit Failure) | Faulty main unit of power steering control module | < Refer to DTC C2532 ECU FAILURE 2 (PERIPHERAL CIRCUIT FAILURE) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2533 | ECM Failure 3 (Board Temperature Sensor Failure) | Faulty main unit of power steering control module | < Refer to DTC C2533 ECM FAILURE 3 (BOARD TEMPERATURE SENSOR FAILURE) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2541 | Vehicle Speed Is Abnormal | Poor connector contact Forgot to connect connector Harness open/short circuit | < Refer to DTC C2541 VEHICLE SPEED IS ABNORMAL , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2543 | Error Passive Status | Defective CAN communication | < Refer to DTC C2543 ERROR PASSIVE STATUS , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2551 | Power Supply Relay Failure | Power supply voltage malfunction Faulty relay contact | < Refer to DTC C2551 POWER SUPPLY RELAY FAILURE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| C2552 | Motor Relay Abnormal | Faulty relay | < Refer to DTC C2552 MOTOR RELAY ABNORMAL , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| U0073 | Control Module Communication Bus "A" Off | Defective CAN communication | < Refer to DTC U0073 CONTROL MODULE COMMUNICATION BUS "A" OFF , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| U0122 | Lost Communication With Vehicle Dynamics Control Module | Defective CAN communication | < Refer to DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| U0416 | Invalid Data Received From Vehicle Dynamics Control Module | Defective CAN communication | < Refer to DTC U0416 INVALID DATA RECEIVED FROM VEHICLE DYNAMICS CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |
| U1120 | Lost Communication With Autostart Stop Control Module | Defective CAN communication | < Refer to DTC U1120 LOST COMMUNICATION WITH AUTOSTART STOP CONTROL MODULE , Diagnostic Procedure with Diagnostic Trouble Code (DTC). > |