Scania BMU DTC 522 Time-out in TMS CAN node

BMU Battery Management Unit · Scania · 2 variants

Code 522 (decimal). Some diagnostic tools show it in hexadecimal as 020A.

In short

Communication with TMS has been interrupted.

Variant 1

Applies to: BMU6 (RES)BMU6 (RESXA)BMU6 (RESXB)BMU6 (RESXC)BMU6 (RESXD)BMU6 (RESXE)BMU6 (RESXF)BMU6 (RESXG)BMU6 (RESXH)BMU6 (RESXI)BMU6 (RESXJ)BMU6 (RESXK)

What does Scania BMU fault code 522 mean?

Communication with TMS has been interrupted.

What causes Scania DTC 522?

Electric power supply to TMS missing. The TMS unit is disconnected from TMS SUB CAN. Faulty TMS unit.

How does the system react?

Functions which are dependent on information from TMS may be downgraded, e.g.: - Request for cooling missing. - Request for status missing.

How to fix Scania BMU fault code 522?

  1. Check the fault codes in TMS.
  2. Check the following if no fault codes can be found in TMS:
  3. Electric power supply, 15 voltage to TMS.
  4. Cable harness and harness-to-component connectors for TMS SUB CAN.

Variant 2: Timeout in GMS CAN node

Applies to: BMU5

Detection

Communication with the GMS interrupted. The fault code becomes active if the CAN message has been missing for 200 ms. The fault code becomes inactive when the CAN message is received. The fault code is not set in the following scenarios: - if 15 voltage is off. - during the first 2 seconds after the 15 voltage has been switched on. - if the supply voltage is below 22 V. - if the supply voltage is above 32 V. - in the event of a short circuit or open circuit on HEV-CAN.

Possible cause

Electric power supply to GMS missing. The GMS unit is disconnected from HEV-CAN. Faulty GMS unit.

Symptoms

Functions which are dependent on information from GMS can be deprioritised, e.g.: - Request for cooling missing. - Request for status missing.

How to fix

  1. Check fault codes in the GMS (E5).
  2. Check the following if no fault codes are found in the GMS:
  3. Electric power supply (pin A4) and signal for the 15 voltage (pin A1) on the harness-to-component connector to the GMS (E5).
  4. Cable routing and harness-to-component connectors for HEV-CAN (pin B11 and pin B14 on the connector to E5).
  5. Disconnect the 24 V battery and measure the resistance on the harness-to-component connector to BMU E81 between CAN-high (pin B5) and CAN-low (pin B8).
  6. The value should be close to 60 ohms (a 120 ohm resistor is located at each end of the CAN bus).

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

Code 522 in other Scania systems

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