Section 349 (Electric Motor Power Steering - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Diagnosis System
1. Check the indicator.
  When the ignition switch is turned ON, check that the PS warning light goes on for 1.5 seconds.
  NOTE:
  - If the indicator check result is not normal, proceed to troubleshooting for the PS warning light circuit. See DTC C1556/56: P/S WARNING LIGHT CIRCUIT .
  - When the EMPS system is faulty, the master warning light in the combination meter and the PS warning light in the multi-information display lights up.
  Fig 1: Identifying Service Reminder Indicators & Indicator Lights
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Identifying Master Warning Light & Service Reminder Indicators
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. In case of not using TOYOTA hand-held tester:
  Check the DTC .
  1. Using SST, connect terminals Tc and CG of the DLC3.
    SST 09843-18040
    
    Fig 3: Locating Terminals Tc & CG Of DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Remove the EMPS ECU with connector still connected.
  3. Connect the both terminals of the 1 k/Ohm resistance and LED (Light Emitting Diode) circuit to terminals WL and PGND of the EMPS ECU.
    
    Fig 4: Locating EMPS ECU Terminals WL & PGND
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Turn the ignition switch ON.
  5. Read the DTC from the PS warning light.
    NOTE:
    If no code appears, inspect the diagnostic circuit and PS warning light circuit. See Tc TERMINAL CIRCUIT or DTC C1556/56: P/S WARNING LIGHT CIRCUIT .
    
    As an example, the blinking patterns for normal code and codes 21 and 22 are shown.
    
    Fig 5: Displaying Diagnostic Trouble Codes 21 & 22
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. Codes are explained in the DTC chart. See DIAGNOSTIC TROUBLE CODE CHART .
  7. After completing the check, disconnect terminals Tc and CG of the DLC3, and turn off the display.
    If 2 or more malfunctions are indicated at the same time, the lowest numbered DTC will be displayed first.
3. In case of using TOYOTA hand-held tester:
  Check the DTC .
  1. Hook up the TOYOTA hand-held tester to the DLC3.
    
    Fig 6: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Turn the ignition switch ON.
  3. Read the DTC by following the prompts on the tester screen.
    NOTE: Please refer to the TOYOTA hand-held tester operator's manual for further details.
4. In case of not using TOYOTA hand-held tester:
  Clear the DTC .
  1. Using SST, connect terminals Ts and CG of DLC3.
    SST 09843-18040
  2. Turn the ignition switch ON.
  3. ON and OFF the terminal CG of the DLC3 4 times or more within 8 seconds, delete DTC of the EMPS ECU.
  4. Check that the PS warning light shows the normal code.
  5. Remove the SST from the DLC3.
    
    Fig 7: Locating Terminals Ts & CG Of DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. In case of using TOYOTA hand-held tester:
  Clear the DTC .
  1. Hook up the TOYOTA hand-held tester to the DLC3.
    
    Fig 8: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Turn the ignition switch ON.
  3. Operate the TOYOTA hand-held tester to erase the codes. (See TOYOTA hand-held tester operator's manual.)

Input Signal Check (Test Mode) .

In case of not using TOYOTA hand-held tester:
Check the input signal.
1. Turn the ignition switch OFF.
2. Using SST, connect terminals Ts and CG of DLC3.
  SST 09843-18040
3. Check that the warning light goes off with driving more than 20 km/h (12 mph).
  NOTE: If the warning light goes off during driving, the sensor can be judged to be normal.
  
  Fig 9: Locating DLC3 Terminals Ts, Tc & CG
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Stop the vehicle.
5. Using SST, connect terminals Tc and CG of DLC3.
  SST 09843-18040
6. Read the number of blinks of the PS warning light.
  NOTE:
  See the list of DTCs shown in INPUT SIGNAL CHECK FUNCTION DTCS .
  
  Even if a sensor is normal, it outputs codes 71 and 72 during test mode.
  
  Fig 10: Displaying Normal Code & Example Of Malfunction Code 72
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
7. After doing check, disconnect the SST from the terminals Ts and CG, Tc and CG of DLC3, and turn the ignition switch OFF.
  SST 09843-18040

In case of using TOYOTA hand-held tester:

Check the input signal .

Hook up the TOYOTA hand-held tester to the DLC3.

Fig 11: Connecting Hand Held Tester To DLC3
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Check that the warning light goes off with driving more than 20 km/h (12 mph).
Read the DTCs by following the prompts on the tester screen.

NOTE:

Please refer to the TOYOTA hand-held tester operator's manual for further details.
See the list of DTC shown in INPUT SIGNAL CHECK FUNCTION DTCS .
Even if a sensor is normal, it outputs codes 71 and 72 during test mode.

INPUT SIGNAL CHECK FUNCTION DTC'S

DTC/Diagnosis		Trouble Area
C1515/15
Calibration Of Torque Sensor Zero Point Not Performed		.....
C1516/16
Calibration Of Torque Sensor Zero Point Not Completed		.....
C1571/71 & C1572/72
Speed Sensor Or Malfunction (Test Mode)		Right Or Left Rear Speed Sensor, Sensor Installation, Rotor, Circuit, Brake Or EMPS ECU

Calibration Of Torque Sensor Zero Point
NOTE:
Perform this operation in the following cases :
- When removing and installing steering wheel, tilt steering column and electric power steering gear.
- When replacing EMPS ECU.
1. Place front wheels and steering wheel facing straight ahead.
2. In case of using TOYOTA hand-held tester:
  Perform the torque sensor zero point initialization (W/Hand Held Tester).
  1. Stop the vehicle.
  2. Hook up the TOYOTA hand-held tester to the DLC3.
    
    Fig 12: Connecting Hand Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Select the "TRQ SENS ADJUST" mode on the TOYOTA hand-held tester.
  4. Select the "ZERO POINT INITIALIZE".
  5. Following the screen instructions, perform the torque sensor zero point initialization.
    NOTE: Please refer to the TOYOTA hand-held tester operator's manual for further details.
3. In case of not using TOYOTA hand-held tester:
  Perform the torque sensor zero point initialization .
  1. Stop the vehicle.
  2. Using SST, connect terminals Ts and CG of DLC3.
    SST 09843-18040
    
    Fig 13: Locating DLC3 Terminals Ts, Tc & CG
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Using SST, connect terminals Tc and CG of DLC3.
  4. ON and OFF the terminal Tc of DLC3 20 times within 20 seconds.
  5. Check that the DTC C1515/15.
4. In case of using TOYOTA hand-held tester:
  Perform the torque sensor zero point calibration .
  
  NOTE: Don't touch the steering wheel.
  1. Select the "TRQ SENS ADJUST" mode on the TOYOTA hand-held tester.
  2. Select the "ZERO POINT ADJUST".
  3. Following the screen instructions, perform the torque sensor zero point calibration.
    NOTE: Please refer to the TOYOTA hand-held tester operator's manual for further details.
    
    Fig 14: Locating DLC3 Terminals Tc & CG
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. In case of not using TOYOTA hand-held tester:
  Perform the torque sensor zero point calibration .
  NOTE:
  - Don't touch the steering wheel.
  - Check the DTC except C1515/15 is not output.
  1. Stop the vehicle and turn the ignition switch OFF.
  2. Using SST, connect terminals Ts and CG of DLC3 and ignition switch ON.
    SST 09843-18040
  3. Disconnect the SST. SST 09843-18040.
    
    Fig 15: Locating DLC3 Terminals Ts & CG
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002