Scania COO DTC 523 Brake pedal sensor

COO Coordinator · Scania · 6 variants

Code 523 (decimal). Some diagnostic tools show it in hexadecimal as 020B.

In short

The voltage in the brake pedal sensor circuit has been lower than permitted. The brake pedal sensor generates 2 separate output signals. The fault applies to the normal output signal.

Variant 1

Applies to: COO10 (COO)

What does Scania COO fault code 523 mean?

The voltage in the brake pedal sensor circuit has been lower than permitted. The brake pedal sensor generates 2 separate output signals. The fault applies to the normal output signal.

What causes Scania DTC 523?

- Short circuit to voltage or break in the circuit for the brake pedal sensor connection to earth. - Internal fault in the brake pedal sensor. - Fault in the brake pedal mechanism. - Fault in harness-to-component connector.

How does the system react?

- Yellow warning indication of a fault in advanced emergency braking (AEB) is displayed. - Yellow warning indication of a fault in the cruise control is displayed. - Cruise control deactivated. - Adaptive cruise control deactivated. - Collision mitigation deactivated and functions dependent on brake pedal sensor degraded.

What are the symptoms?

- When the fault is active, the brake light remains lit. - Exhaust brake activation may be impaired. - The emergency brake and cruise control will not work while the fault is active.

How to fix Scania COO fault code 523?

  1. Check the brake pedal sensor's cable harness.
  2. Check the brake pedal sensor's harness-to-harness connector.
  3. Check the brake pedal sensor mechanism.
  4. Check the brake pedal mechanism.
  5. Measure the voltage from the brake pedal sensor output signal to earth.

Variant 2: Ordinary brake pedal sensor, short circuit to voltage supply

Applies to: COO11 (COO)

Detection

The voltage in the brake pedal sensor circuit has been higher than permitted. This indicates a short circuit to voltage supply.

Possible cause

- Short circuit to voltage or break in the circuit for the brake pedal sensor connection to earth. - Internal fault in the brake pedal sensor. - Fault in the brake pedal mechanism. - Fault in harness-to-component connector.

Symptoms

When the fault is active, the brake light remains lit. Exhaust brake activation does not work well. CAN message about fault related to the brake pedal is displayed. The emergency brake and collision warning will not work while the fault is active. Cruise control and adaptive cruise control have impaired function as long as the fault is active.

How to fix

  1. Check the brake pedal sensor's cable harness.
  2. Check the brake pedal sensor's harness-to-harness connector.
  3. Check the brake pedal sensor mechanism.
  4. Check the brake pedal mechanism.
  5. Measure the voltage from the brake pedal sensor output signal to earth.

Variant 3

Applies to: COO8 (COO)

Detection

The voltage in the brake pedal sensor circuit has been above the permitted level. The brake pedal sensor generates two separate output signals and the fault applies to the normal output signal.

Possible cause

- Short circuit to voltage or break in the circuit for the brake pedal sensor connection to earth. - Internal fault in the brake pedal sensor. - Fault in the brake pedal mechanism. - Fault in harness-to-component connector.

Symptoms

When the fault is active, the brake light remains lit. It is also possible that activation of the exhaust brake may not work properly. Collision warning, emergency braking, cruise control and adaptive cruise control will not work while the fault is active.

How to fix

  1. Check the brake pedal sensor's cable harness.
  2. Check the brake pedal sensor's harness-to-harness connector.
  3. Check the brake pedal sensor mechanism.
  4. Check the brake pedal mechanism.
  5. Measure the voltage from the brake pedal sensor output signal to earth.

Variant 4

Applies to: COO9 (COO)

Detection

The voltage in the brake pedal sensor circuit has been above the permitted level. The brake pedal sensor generates two separate output signals and the fault applies to the normal output signal.

Possible cause

The fault may be due to: - Short circuit to voltage or open circuit in the brake pedal sensor's connection to ground. - Internal fault in the brake pedal sensor. - Faulty brake pedal mechanism. - Fault in the harness-to-component connector.

Symptoms

When the fault is active, the brake light remains lit. It is also possible that activation of the exhaust brake may not work properly. Collision warning, emergency braking, cruise control and adaptive cruise control will not work while the fault is active.

How to fix

  1. Check the brake pedal sensor including cable harness and harness-to-harness connectors.
  2. Check the brake pedal mechanism.
  3. Measure the voltage from the brake pedal sensor output signal to ground.

Variant 5

Applies to: COO7

Detection

The voltage in the brake pedal sensor circuit has been above the permitted level. The brake pedal sensor generates two separate output signals and the fault applies to the normal output signal.

Possible cause

The fault may be due to: - Short circuit to voltage or open circuit in the brake pedal sensor's connection to ground. - Internal fault in the brake pedal sensor. - Faulty brake pedal mechanism.

System reaction

When the fault is active, the brake light remains lit. It is also possible that activation of the exhaust brake may not work properly. Collision warning, cruise control and adaptive cruise control will not work while the fault is active.

How to fix

  1. Check the brake pedal sensor including cable harness and harness-to-harness connectors.
  2. Check the brake pedal mechanism.

Variant 6

Applies to: COO8

Detection

The voltage in the brake pedal sensor circuit has been above the permitted level. The brake pedal sensor generates two separate output signals and the fault applies to the normal output signal.

Possible cause

The fault may be due to: - Short circuit to voltage or open circuit in the brake pedal sensor's connection to ground. - Internal fault in the brake pedal sensor. - Faulty brake pedal mechanism. - Fault in the harness-to-component connector.

System reaction

When the fault is active, the brake light remains lit. It is also possible that activation of the exhaust brake may not work properly. Collision warning, emergency braking, cruise control and adaptive cruise control will not work while the fault is active.

How to fix

  1. Check the brake pedal sensor including cable harness and harness-to-harness connectors.
  2. Check the brake pedal mechanism.
  3. Measure the voltage from the brake pedal sensor output signal to earth.

This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.

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