Knorr KB3TA fault code reading


An LED on the ECU shows status and fault codes in the system

The LED is not on: No power to the ECU.

LED on with green light: The ECU has power. No active fault codes.

LED flashes red: The ECU has power. There are active fault codes in the system, flashes show in which component the fault is active.

LED on with red light: The ECU is defective.

Flash codes are generated by bridging pin 5 and 7 in the diagnostics socket.

To generate fault codes

- Bridge pin 5 and 7 for 2 seconds.

- Remove bridging.

- Bridge pin 5 and 7 for 2 seconds.

- Remove bridging.

- The green LED flashes to show configuration (see fault code list).

- LED turns off for 5 seconds.

- The red LED flashes to show the defective component, (see fault code list).

- LED turns off for 2 seconds.

- The yellow LED flashes to show type of fault in the component (see fault code list).

- LED turns off for 5 seconds.

- If several fault codes are stored in the system the flash sequence starts over.

 ConfigurationDefective componentType of fault
Flash pulsesGreenRedYellow
1   
22S/2MSensor left 1Open circuit
34S/4MSensor left 2Short-circuiting
4 Sensor right 1Short-circuiting to battery
54S/3MSensor right 2Dynamic sensor failure
6 Sensor left axle 
7 Sensor right axle 
8 Modulator left 
9 Modulator right 
10 Modulator axle 
11 Power supply2-for low, 3- For high, 4- Open circuit (ground)
12 Continuous brake 
13   
14   
15 Internal error/System failure 

After the fault has been solved, the fault codes must be erased using the following procedure.

- Bridge pin 5 and 7 for 2 seconds.

- Remove bridging.

- Bridge pin 5 and 7 for 2 seconds.

- Remove bridging.

- Bridge pin 5 and 7 for 2 seconds.

- Remove bridging.

- LED flashes red for 3 seconds.

- LED flashes red/green for 3 seconds, bridge pin 5 and 7 for 1 second during this phase.

- LED turns off for 1 second.

- LED flashes yellow for 2 seconds.

- fault codes have been erased.