Variant 1: CAN bus switch modules
Applies to: COO10 (COO)
What does Scania COO fault code 875 mean?
All communication for switch modules on the CAN bus has been interrupted.
What causes Scania DTC 875?
- Open circuit in the CAN bus cable harness for switch modules. - Short circuit in the CAN bus cable harness for switch modules. - External damage or crush damage on the cable harness. - Internal fault in one of the units for switch modules in the CAN bus. - The connected control unit communicating at 250 kb/s.
How does the system react?
Multiple warnings are displayed in the instrument cluster.
What are the symptoms?
Functions dependent on information from the CAN bus for switch modules are impaired.
How to fix Scania COO fault code 875?
- Check the CAN bus cable harnesses and harness-to-harness connectors.
- Check that there is no crush damage or external damage on the cable harness.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high (pin D1) and CAN-low (pin D10).
- The resistance should be approx.
- 60 ohms.
- (Due to the two termination resistors connected in parallel.)
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high and voltage supply.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high and earth.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-low and voltage supply.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-low and earth.
- The resistance should be in the order of a Megaohm.
- Disconnect one unit at a time from the CAN bus to see if the fault disappears.
- Also check the connections and pins of the units.
Variant 2: CAN bus switch modules, communication error
Applies to: COO11 (COO)
Detection
All communication for switch modules on the CAN bus has been interrupted.
Possible cause
- Open circuit in the CAN bus cable harness for switch modules. - Short circuit in the CAN bus cable harness for switch modules. - External damage or crush damage on the cable harness. - Internal fault in one of the units for switch modules in the CAN bus. - The connected control unit communicating at 250 kb/s.
System reaction
Several warnings are displayed in the driver display.
Symptoms
Functions dependent on information from the CAN bus for switch modules are impaired.
How to fix
- Check the CAN bus cable harnesses and harness-to-harness connectors.
- Check that there is no crush damage or external damage on the cable harness.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high (pin D1) and CAN-low (pin D10).
- The resistance should be approx.
- 60 ohms.
- (Due to the two termination resistors connected in parallel.)
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high and voltage supply.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-high and earth.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-low and voltage supply.
- The resistance should be in the order of a Megaohm.
- Disconnect the battery.
- Measure the resistance between the coordinator pin on the CAN bus for CAN-low and earth.
- The resistance should be in the order of a Megaohm.
- Disconnect one unit at a time from the CAN bus to see if the fault disappears.
- Also check the connections and pins of the units.
Variant 3
Applies to: COO8 (COO)
Detection
All communication on the CAN bus for switch modules has been interrupted.
Possible cause
- Open circuit in the CAN bus cable harness for switch modules. - Short circuit in the CAN bus cable harness for switch modules. - External damage or crush damage on the cable harness. - Internal fault in one of the units for switch modules in the CAN bus. - The connected control unit communicating at 250 kb/s.
System reaction
Several warnings are displayed in the instrument cluster.
Symptoms
Functions dependent on information from the CAN bus for switch modules are impaired.
How to fix
- Check the CAN bus cable harnesses and harness-to-harness connectors.
- Check that there is no crush damage or external damage on the cable harness.
- Measure the resistance between the coordinator pins for CAN high (B7) and CAN low (B16) of the CAN bus with the battery disconnected.
- Resistance should be around 60 ohms.
- (Due to the two termination resistors connected in parallel.)
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Disconnect one unit from the CAN bus at a time to see if the fault disappears.
- Also check the connections and pins of the units.
Variant 4
Applies to: COO9 (COO)
Detection
All communication on the CAN bus for switch modules has been interrupted.
Possible cause
The fault may be due to: - Short circuit in the CAN bus for switch modules circuit. - External damage or crush damage on the cable harness. - Internal fault in one of the units on the CAN bus for switch modules. - Connected control unit which communicates at 250 kb/s.
System reaction
Several warnings are displayed in the instrument cluster.
Symptoms
Functions dependent on information from the orange CAN bus are impaired.
How to fix
- Check the CAN bus cable harnesses and harness-to-harness connectors.
- Check that there is no crush damage or external damage on the cable harness.
- Measure the resistance between the coordinator pins for CAN high (B7) and CAN low (B16) of the CAN bus with the battery disconnected.
- Resistance should be around 60 ohms.
- (Due to the two termination resistors connected in parallel.)
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Disconnect one unit from the CAN bus at a time to see if the fault disappears.
- Also check the connections and pins of the units.
Variant 5
Applies to: COO8
Detection
All communication on the CAN bus for switch modules has been interrupted.
Possible cause
The fault may be due to: - Short circuit in the CAN bus for switch modules circuit. - Internal fault in one of the units on the CAN bus for switch modules. - Connected control unit which communicates at 250 kb/s.
System reaction
- Multiple warnings are displayed in the instrument cluster. - Functions dependent on information from the CAN bus for switch modules are impaired.
How to fix
- Check the CAN bus cable harnesses and connectors.
- Measure the resistance between the coordinator pins of the CAN bus's CAN high (B7) and CAN low (B16) with the battery disconnected.
- Resistance should be around 60 ohms.
- (Due to the two termination resistors connected in parallel.)
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN high of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and voltage with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Measure the resistance between the coordinator pin for CAN low of the CAN bus and ground with the battery disconnected.
- Resistance should be in the order of Megaohms.
- Disconnect one unit from the CAN bus at a time to see if the fault disappears.
- Also check the connections and pins of the units.
This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.