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Fig. 3.7 Diagnostic codes as given in a Toyota workshop manual

Fig. 3.7 Diagnostic codes as given in a Toyota workshop manual

3.1.2 METHOD 2: FAULT CODES DISPLAYED THROUGH A LOGIC PROBE OR TEST LAMP

Figure 3.8 shows the circuit, and details of the method that can be used to obtain fault codes, from a Wabco braking system.

The procedure, as taken from the Wabco publication 'Blinkcode for Goods Vehicles and Buses ABS/ASR ''C''-Generation' gives the procedure as follows.

1. In the case of a vehicle not having an ASR lamp installed: connect a filament bulb (2W.. .5W) to pin 3 of the ECU (see top circuit diagram). This can be achieved using Wabco inter-adaptor installed between ECU and ECU connector (Ignition:OFF!).

2. By connecting pin 14 to vehicle ground (earth) for longer than 5 seconds this can be achieved via the switch on the inter-adaptor (Ignition:ON!).

3. The blinkcode can be read and noted until the user is in no doubt as to the transmitted fault code! The fault code can be erased by disconnecting pin 14 from vehicle ground during the blinkcode transmission.

To prevent inadvertent erasure of fault codes, the ignition should be switched off during blinkcode transmission. Faults actually present must first be repaired before further fault codes can be read. Following each repair the blinkcode should be reactivated to ensure that no further faults exist and the fault memory of the ECU is cleared. When all faults have been read and erased, the code for 'System OK' is transmitted (i.e., X-0-0).

After each repair the system operation should be further verified by a test drive during which the ABS and ASR lamps should extinguish once the vehicle has reached 7 km/h.

The blinkcode frame is made up as shown in Fig. 3.9.

3.1.3 METHOD 3: FAULT CODE READERS AND SCAN TOOLS

Fault code readers vary in complexity from inexpensive devices that read out flash codes, such as the Gunson 'Fault Finder' shown in Fig. 3.10, to

BLINKCODE CONNECTION: WITHOUT ISO 9141 - SOCKET WITHOUT ASR LAMP
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