Diagnosis System

WARNING: This page is about a different car, the 2011 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.

DESCRIPTION

DIAGNOSTIC SYSTEM
When troubleshooting a vehicle with a diagnostic system, the only difference from the usual troubleshooting procedure is connecting Techstream to the vehicle and reading various data output from the vehicle's steering lock ECU.

The steering lock ECU records DTCs when the computer detects a malfunction in the computer itself or in its circuits.

To check the DTCs, connect Techstream to the DLC3 on the vehicle. Techstream enables clearing the DTCs, activating indicators and checking the data list.
The diagnosis information of the steering lock ECU is transmitted to the tester via the certification ECU as the steering lock ECU is not connected to the BEAN.

Check the DLC3.

The certification ECU follows the ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

Fig 1: Identifying DLC3 Connector Terminal Identification

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Symbols (Terminals No.)	Terminal Description	Condition	Specified Condition
SIL(7) - SG(5)	Bus "+" line	During communication	Pulse generation
CG(4) - Body ground	Chassis ground	Always	Below 1 Ω
SG(5) - Body ground	Signal ground	Always	Below 1 Ω
BAT(16) - Body ground	Battery positive	Always	11 to 14 V

HINT:

If the display shows a communication error message after connecting the Techstream cable to the DLC3 and turning the engine switch on (IG), there is a problem with either the vehicle or tester.
If communication is normal when connecting the tester to another vehicle, inspect the DLC3 on the original vehicle.
If communication is still not possible when connecting the tester to another vehicle, the problem is probably on the tester itself, so consult the Service Department listed in the tester's operator's manual.

WARNING FUNCTION OF ENGINE SWITCH INDICATOR

The steering lock ECU blinks the LED indicator of the engine switch when any of the following problems occurs in the system.

Fig 2: Identifying Indicator Light

Detection item	Indicator light blink pattern	Indication status	Countermeasure
Steering lock is still not released	Blinks green at 1-second intervals Goes off 15 seconds after blinking starts	The motor operates to release the steering lock, but the steering lock cannot be released (e.g. the lock bar is stuck in the steering column).	Push the engine switch while turning the steering wheel left and right.
Malfunction in push button start function	Blinks amber at 2-second intervals Goes off 15 seconds after the engine switch is turned off while blinking	There is a short in the devices activating the motor. There is a problem in the steering lock ECU or power source control ECU assembly.	Troubleshoot by following "HOW TO PROCEED WITH TROUBLESHOOTING". Refer to HOW TO PROCEED WITH TROUBLESHOOTING .

WARNING FUNCTION OF COMBINATION METER

The steering lock ECU displays a warning on the combination meter when any of the following problems occurs in the system.

Detection item	Display	Indication status	Countermeasure
Steering lock is still not released	"S/T is not Unlocked" Goes off 15 seconds after blinking starts	The motor operates to release the steering lock, but the steering lock cannot be released (e.g. the lock bar is stuck in the steering column).	Push the engine switch while turning the steering wheel left and right.
Malfunction in push button start function	"Check S/T Lock" Goes off 15 seconds after the engine switch is turned off while blinking	There is a short in the devices activating the motor. There is a problem in the steering lock ECU or power source control ECU assembly.	Troubleshoot by following "HOW TO PROCEED WITH TROUBLESHOOTING". Refer to HOW TO PROCEED WITH TROUBLESHOOTING .