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STEP 4: Blink Codes for Knorr-Bremse EU12 & U16 System ECU

  1. Use the table to identify ABS faults from the ECU Blink Codes recorded in STEP 3: Blink code identification and system response
  2. Links to solutions for common ABS faults can also be found below
  3. Please ensure all necessary Health and Safety precautions are implemented before commencing any repair work
  4. A list of useful ABS Diagnostic Tools is available on this website
  5. If you require further help or information, please contact us

Knorr-Bremse EU12 System ECU

Knorr-Bremse U16 System ECU

Code Displayed

Location

Type of Fault

1st Digit

2nd Digit

1

1

No fault

2

1

Wheel speed sensor, steer axle, left

Air gap too big

2

2

Missing sensor signal at drive off

2

3

Damaged/contaminated tooth on exciter ring, long term ABS control

2

4

Long term instability

2

5

Loss of speed sensor signal

2

6

Shorted to ground or battery or broken wire

2

7

Internal fault

2

8

Sensor configuration error

3

1

Wheel speed sensor, steer axle, right

Air gap too big

3

2

Missing sensor signal at drive off

3

3

Damaged/contaminated tooth on exciter ring, long term ABS control

3

4

Long term instability

3

5

Loss of speed sensor signal

3

6

Shorted to ground or battery or broken wire

3

7

Internal fault

3

8

Sensor configuration error

4

1

Wheel speed sensor, drive axle, left

Air gap too big

4

2

Missing sensor signal at drive off

4

3

Damaged/contaminated tooth on exciter ring, long term ABS control

4

4

Long term instability

4

5

Loss of speed sensor signal

4

6

Shorted to ground or battery or broken wire

4

7

Internal fault

4

8

Sensor configuration error

5

1

Wheel speed sensor, drive axle, right

Air gap too big

5

2

Missing sensor signal at drive off

5

3

Damaged/contaminated tooth on exciter ring, long term ABS control

5

4

Long term instability

5

5

Loss of speed sensor signal

5

6

Shorted to ground or battery or broken wire

5

7

Internal fault

5

8

Sensor configuration error

6

1

Wheel speed sensor, additional axle, left

Air gap too big

6

2

Missing sensor signal at drive off

6

3

Damaged/contaminated tooth on exciter ring, long term ABS control

6

4

Long term instability

6

5

Loss of speed sensor signal

6

6

Shorted to ground or battery or broken wire

6

7

Internal fault

6

8

Sensor configuration error

7

1

Wheel speed sensor, additional axle, right

Air gap too big

7

2

Missing sensor signal at drive off

7

3

Damaged/contaminated tooth on exciter ring, long term ABS control

7

4

Long term instability

7

5

Loss of speed sensor signal

7

6

Shorted to ground or battery or broken wire

7

7

Internal fault

7

8

Sensor configuration error

8

1

Pressure modulator valve, steer axle, left

Release solenoid shorted to battery

8

2

Release solenoid shorted to ground

8

3

Release solenoid broken wire

8

4

Valve ground broken wire

8

5

Hold solenoid shorted to battery

8

6

Hold solenoid shorted to ground

8

7

Hold solenoid broken wire

8

8

Valve configuration error

8

10

Additional output stages (IAD)

IAD shorted to battery

8

11

IAD shorted to ground or broken wire

9

1

Pressure modulator valve, steer axle, right

Release solenoid shorted to battery

9

2

Release solenoid shorted to ground

9

3

Release solenoid broken wire

9

4

Valve ground broken wire

9

5

Hold solenoid shorted to battery

9

6

Hold solenoid shorted to ground

9

7

Hold solenoid broken wire

9

8

Valve configuration error

9

10

Additional output stages (IAD)

2nd stage shorted to battery

9

11

2nd stage shorted to ground or broken wire

10

1

Pressure modulator valve, drive axle, left

Release solenoid shorted to battery

10

2

Release solenoid shorted to ground

10

3

Release solenoid broken wire

10

4

Valve ground broken wire

10

5

Hold solenoid shorted to battery

10

6

Hold solenoid shorted to ground

10

7

Hold solenoid broken wire

10

8

Valve configuration error

10

10

Pressure modulator valve, ground switches

Ground wire on diagonal 1, shorted to battery

10

11

Ground wire on diagonal 1, shorted to ground

11

1

Pressure modulator valve, drive axle, right

Release solenoid shorted to battery

11

2

Release solenoid shorted to ground

11

3

Release solenoid broken wire

11

4

Valve ground broken wire

11

5

Hold solenoid shorted to battery

11

6

Hold solenoid shorted to ground

11

7

Hold solenoid broken wire

11

8

Valve configuration error

11

10

Pressure modulator valve, ground switches

Ground wire on diagonal 2, shorted to battery

11

11

Ground wire on diagonal 2, shorted to ground

12

1

Pressure modulator valve, additional axle, left

Release solenoid shorted to battery

12

2

Release solenoid shorted to ground

12

3

Release solenoid broken wire

12

4

Valve ground broken wire

12

5

Hold solenoid shorted to battery

12

6

Hold solenoid shorted to ground

12

7

Hold solenoid broken wire

12

8

Valve configuration error

13

1

Pressure modulator valve, additional axle, right

Release solenoid shorted to battery

13

2

Release solenoid shorted to ground

13

3

Release solenoid broken wire

13

4

Valve ground broken wire

13

5

Hold solenoid shorted to battery

13

6

Hold solenoid shorted to ground

13

7

Hold solenoid broken wire

13

8

Valve configuration error

14

1

ATC valve

N/A

14

2

N/A

14

3

N/A

14

4

N/A

14

5

Shorted to battery

14

6

Shorted to ground

14

7

Broken wire

14

8

Valve configuration error

14

9

Engine control interface

J1939: NA; J1922: NA; PWM-DKR: shorted to ground or battery

14

10

J1939: NA; J1922: NA; PWM-EDC: reports error

14

11

J1939-CN12 only: broken wire or short circuit to ground, or plus on CAN wire after power on; J1922: NA; PWM: broken wire or shorted to battery or ground on DKV

14

12

J1939: Timeout or data out of range on EEC1; J1922: Timeout MID 69; PWM: timing error on frequency or pulse width

15

1

ECU internal failures

Internal

15

2

Internal

15

3

Internal

15

4

Internal

15

5

Internal

15

6

Internal

15

7

Internal

15

9

Internal

15

10

Internal

15

11

Internal

15

12

Internal

16

1

Power supply

PCV1 voltage too high

16

2

PCV1 voltage too low

16

3

PCV1 broken wire

16

4

GRN_PCV1 broken wire or voltage difference to GRN_ECU too large

16

5

PCV2 voltage too high

16

6

PCV2 voltage too low

16

7

PCV2 broken wire

16

8

GRN_PCV2 broken wire or voltage difference to GRN_ECU too large or broken wire on valve common pin on 4S/3M configurations

16

9

U_ECU voltage too high

16

10

U_ECU voltage too low (or E_ECU too high)

16

11

Voltage difference PCV1 to PCV2 too large

17

1

Retarder relay

Retarder disable relay output shorted to battery or broken wire

17

2

Retarder disable relay output shorted to ground

17

3

J1922: interface shorted; J1939 interface has BUS-off detected

17

4

J1922: timeout of MID 83; J1939 timeout of ERC1

17

5

Tyre size alignment

Difference of front to rear tyre size too large

17

6

Measured values out of range or EEPROM values faulty

17

7

Special errors

Stop light switch not operated during this power cycle

17

8

ATC disabled due to special mode or off-road ATC activity

17

9

Off-road ABS active

17

10

WL defective

17

11

TCL defective

17

12

Sensor memory bit set

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