Trouble Shooting: 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.

1. ECU Terminal Values Measurement By Using Toyota Break-Out-Box And Toyota Hand-Held Tester :
1. Hook up the break-out-box and TOYOTA hand-held tester to the vehicle. See Fig 3 and Fig 4 .
2. Read the ECU input/output values by following the prompts on the tester screen.
3. Please refer to the TOYOTA hand-held tester has a "Snapshot" function. This records the measured data and is effective in the diagnosis of intermittent problems.
Using Toyota Hand-Held Tester :
1. Connect the TOYOTA hand-held tester to the DLC3. See Fig 4.
2. Monitor the ECU data by following the prompts on the tester screen.
Clearing DTCs :
DTC can be deleted using a hand-held tester. If there is no hand-held tester or it cannot be used, disconnect the auxiliary battery for 1 min. or more and connect it again.
Problem Symptom Confirmation (Road Test)
1. Inspect the SET switch, see Figure:
  1. Push the main switch ON. See Figure.
  2. Drive at a desired speed (25 mph (40 km/h) or higher).
  3. Press the control switch to the SET/COAST. See Figure.
  4. After releasing the switch, check that the vehicle cruises at the desired speed.
2. Inspect the ACCEL switch, seeFigure:
  1. Push the main switch ON. See Figure.
  2. Drive at a desired speed (25 mph (40 km/h) or higher).
  3. Check that the vehicle speed increases while the control switch is turned to RES/ACC, seeFigure and that the vehicle cruises at the set speed when the switch is released.
  4. Momentarily press the control switch upward for RES/ACC, seeFigure and then immediately release it. Check that the vehicle speed increases by about 1.5 Km/h (Tap-up function).
3. Inspect the COAST switch, See Figure:
  1. Push the main switch ON. See Figure.
  2. Drive at a desired speed 25 mph (40 km/h) or higher.
  3. Check that the vehicle speed decreases while the control switch is turned to SET/COAST, and the vehicle cruises at the set speed when the switch is released. See Figure.
  4. Momentarily press the control switch is turned to SET/COAST, and then immediately release it. Check that the vehicle speed decreases by about 1.5 km/h (Tap-down function).
4. Inspect the CANCEL switch, see Figure:
  1. Push the main switch ON. See Figure.
  2. Drive at a desired speed 25 mph (40 km/h) or higher.
  3. When operating one of the followings, check that the cruise control system is cancelled and that the normal driving mode is reset.
    Depress the brake pedal.
    
    Shift to except D range (A/T).
    
    Push the main switch OFF.
    
    Pull the cruise control switch to CANCEL. See Figure.
5. Inspect the RESUME switch, see Figure:
  1. Push the main switch ON. See Figure.
  2. Drive at a desired speed 25 mph (40 km/h) or higher.
  3. When operating one of the following, check that the cruise control system is cancelled and that the normal driving mode is reset:
    Depress the brake pedal.
    
    Shift to except "D" range (A/T).
    
    Pull the cruise control switch to CANCEL. See Figure.
  4. After the control switch is turned to RES/ACC, see Figure, at the driving speed of more than 40 km/h (25 mph), check that the vehicle restores the speed prior to the cancellation.
Input Signal Check (Using Hand-Held Tester)
1. Connect the hand-held tester to DLC3. See Fig 4.
2. Check the control switch (MAIN, CANCEL, SET/COAST, RES/ACC). See Figure, Figure, Figure and Figure .

Problem Symptoms Table

Symptom

Suspect Area

See

SET not occurring or CANCEL occurring. (DTC is Normal)

.....

Input Signal Circuit

⁽¹⁾

.....

Vehicle Speed Sensor Circuit

⁽²⁾

.....

Stop Light Switch Circuit

⁽³⁾

.....

Park/Neutral Position Switch Circuit

⁽⁴⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

SET not occurring or CANCEL occurring. (DTC dose not output)

.....

Hybrid vehicle control ECU

⁽⁵⁾

Actual Vehicle Speed Deviates Above Or Below The Set Speed.

.....

Input Signal Circuit

⁽¹⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

Gear shifting occurs frequently between 3rd & O/D when driving on uphill road. (Hunting).

.....

Hybrid vehicle control ECU

⁽⁵⁾

Cruise Control Not Cancelled, Even When Brake Pedal Is Depressed.

.....

Stop Light Switch Circuit

⁽³⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

Cruise control not cancelled, even when transmission is shifted to "N" position.

.....

Park/Neutral Position Switch Circuit

⁽⁴⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

Control switch does not operate. (SET/COAST, ACC/RES, CANCEL not possible)

.....

Cruise Control Switch Circuit

⁽⁶⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

SET possible at 25 mph or less, or CANCEL does not operate at 25 mph or less.

.....

Input Signal Circuit

⁽¹⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

Poor response is ACCEL and RESUME modes.

.....

Hybrid vehicle control ECU

⁽⁵⁾

O/D does not resume, even though the road is not uphill.

.....

Hybrid vehicle control ECU

⁽⁵⁾

DTC memory is erased.

.....

Hybrid vehicle control ECU

⁽⁵⁾

DTC is not output, or is output when should not be

.....

Diagnosis Circuit

⁽⁷⁾

.....

Hybrid vehicle control ECU

⁽⁵⁾

Cruise MAIN indicator light remains ON or falls to light up

.....

Input Signal Circuit

⁽¹⁾

.....

⁽⁵⁾

⁽¹⁾	DTC 1566: INPUT SIGNAL CIRCUIT ABNORMAL

⁽²⁾	DTC P0500 VEHICLE SPEED SENSOR MALFUNCTION under DIAGNOSTICS-ENGINE.

⁽³⁾	DTC P1520: STOP LIGHT SWITCH CIRCUIT

⁽⁴⁾	See, DTC P1780 PARK/NUETRAL POSITION SWITCH MALFUNCTIN under DIAGNOSTICS-ENGINE.

⁽⁵⁾	See, HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS.

⁽⁶⁾	CRUISE CONTROL SWITCH CIRCUIT

⁽⁷⁾	Manufacturer did not define procedure.

Fig 1: Customer Problem Analysis (Cruise Control System Check List)

Fig 2: Trouble Shooting Flow Chart

Fig 3: Connecting Toyota Hand Held Tester

Fig 4: Connecting Toyota Hand Held Tester To DLC3

Fig 5: Diagnostic Trouble Code Chart