Scania CMS DTC 525 CAN communication on the control unit sub data bus 2

CMS CMS control unit · Scania

Code 525 (decimal). Some diagnostic tools show it in hexadecimal as 020D.

In short

Short circuit in the control unit sub data bus 2.

Applies to: CMS1 (CMS)

What does Scania CMS fault code 525 mean?

Short circuit in the control unit sub data bus 2.

What causes Scania DTC 525?

The fault may be due to: Fault in the cable harness of the control unit sub data bus 2. - Short circuit between CAN High and CAN Low. - Short circuit between voltage supply and CAN High. - Short circuit between ground and CAN High. - Short circuit between voltage supply and CAN Low. - Short circuit between ground and CAN Low. - Fault in control units connected to the CAN bus.

What are the symptoms?

Functions dependent on information from the control unit sub data bus 2 are impaired.

How to fix Scania CMS fault code 525?

  1. Check the sub data bus 2 connection to the CMS control unit.
  2. Measure the resistance between the CMS control unit pin for the CAN bus CAN High and CAN Low with the battery disconnected.
  3. Resistance should be around 60 ohms.
  4. (Due to the two termination resistors connected in parallel.)
  5. Measure the resistance between the CMS control unit CAN High and CAN High on other units connected to the sub data bus with the battery disconnected.
  6. Resistance should be close to 0 ohm.
  7. Measure the resistance between the CMS control unit CAN Low and CAN Low on other units connected to the sub data bus with the battery disconnected.
  8. Resistance should be close to 0 ohm.
  9. Check the CMS control unit wake-up signal (15).

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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