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Circuit/System Testing

NOTE:

Each device may need to be disconnected to isolate a circuit fault. Use the schematic to identify the following:

  • FlexRay devices and terminating resistors the vehicle is equipped with
  • Device locations on the FlexRay serial data circuits
  • Each device's ground, B+, ignition, and FlexRay serial data circuit terminals
  1. Refer to Data Link References to determine which devices are on the FlexRay bus.
  2. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. Disconnect the harness connectors with the FlexRay serial data circuits at the K124B Active Safety Control Module 2. It may take up to 10 min for all vehicle systems to power down.
  3. Ignition ON/Vehicle In Service Mode.
  4. Test for less than 4.5 V between each FlexRay serial data circuit at the K124B Active Safety Control Module 2 and ground.
    • If 4.5 V or greater 

      Refer to Testing the Serial Data Circuits for a Short to Voltage.

    • Go to next step: If less than 4.5 V 
  5. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
  6. Test for greater than 100 Ω between each FlexRay serial data circuit at the K124B Active Safety Control Module 2 and ground.
    • If 100 Ω or less 

      Refer to Testing the Serial Data Circuits for a Short to Ground.

    • Go to next step: If greater than 100 Ω 
  7. Test for 90 - 110 Ω between each pair of the FlexRay serial data circuit at the K124B Active Safety Control Module 2.
    • If less than 90 Ω 

      Refer to Testing the Serial Data Circuits for a Short between the Circuits.

    • If greater than 110 Ω 

      Refer to Testing the Serial Data Circuits for an Open/High Resistance.

    • Go to next step: If between 90 - 110 Ω 
  8. Replace the K124B Active Safety Control Module 2.

Testing the Serial Data Circuits for a Short to Voltage

  1. Ignition/Vehicle OFF, disconnect the harness connectors with the FlexRay serial data circuits at another device, in the direction of the circuit shorted to voltage, ignition ON/Vehicle In Service Mode.
  2. Test for greater than 4.5 V between each FlexRay serial data circuit at the device connector that was just disconnected and ground.
    • If each serial data circuit is 4.5 V or less 

      Replace the device that was disconnected.

  3. Repeat step 1 until one of the following conditions are isolated:
    • A short to voltage on the serial data circuit between two devices or splice packs, if equipped.
    • A short to voltage on the serial data circuit between a device and a terminating resistor.

Testing the Serial Data Circuits for a Short to Ground

  1. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
  2. Disconnect the harness connectors with the FlexRay serial data circuits at another device, in the direction of the circuit shorted to ground.
  3. Test for greater than 100 Ω between each FlexRay serial data circuit at the device connector that was just disconnected and ground.
    • If each serial data circuit is 100 Ω or greater 

      Replace the device that was disconnected.

    • Go to next step: If any serial data circuit is less than 100 Ω 
  4. Repeat step 1 until one of the following conditions are isolated:
    • A short to ground on the serial data circuit between two devices or splice packs, if equipped.
    • A short to ground on the serial data circuit between a device and a terminating resistor.

Testing the Serial Data Circuits for a Short between the Circuits

  1. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
  2. Connect the harness connectors at the device that was previously disconnected.
  3. Disconnect the harness connectors with the FlexRay serial data circuits at another device, in the direction of the circuit shorted together.
  4. Test for greater than 90 Ω between each pair of FlexRay serial data circuits at the device connector that was just disconnected.
    • If each pair of serial data circuits is 90 Ω or greater 

      Replace the device that was disconnected.

    • Go to next step: If any pair of serial data circuits is less than 90 Ω 
  5. Repeat step 1 until one of the following conditions are isolated:
    • Serial data circuits shorted together between two devices or splice packs, if equipped.
    • Serial data circuits shorted together between a device and a terminating resistor.
    • A shorted terminating resistor.

Testing the Serial Data Circuits for an Open/High Resistance

  1. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
  2. Connect the harness connectors at the device that was disconnected.
  3. Disconnect the harness connectors with the FlexRay serial data circuits at another device, in the direction of the circuit with the open/high resistance.
  4. Test for less than 110 Ω between each pair of FlexRay serial data circuits at the device connector that was just disconnected.
    • If each pair of serial data circuits is 110 Ω or less 

      Replace the device that was disconnected.

    • Go to next step: If any pair of serial data circuits is greater than 110 Ω 
  5. Repeat step 1 until one of the following conditions are isolated:
    • An open/high resistance on the serial data circuit between two devices or splice packs, if equipped.
    • An open/high resistance on the serial data circuit between a device and a terminating resistor.
    • An open/high resistance terminating resistor.
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