Taking Reading on Cables In the CAN Network (HS-CAN)

Taking Reading On Cables In The CAN Network (HS-CAN)







- Ignition off
- Disconnect the battery negative lead
- Connect the breakout box to the engine control module (ECM).

HINT: Use the Wiring diagrams to provide support when taking readings.

Take resistance readings across the following terminals. Various readings must be taken due to the structure of the network. Twist the cable harness and work the connectors at accessible points along the cable harness in order to check whether the resistance changes during each measurement. This method can be used to detect intermittent short-circuits or open-circuits.

NOTE: The following resistance readings only measure the main arteries in the high speed network, not the junctions that exist for some control modules. See the Wiring diagrams for the relevant car model. An open-circuit in one artery cannot be detected by this reading. However a short-circuit in an artery can be detected.

Measure the resistance between control module terminals #B1(#1) and #B13 (#13). The resistance must be approximately 60 ohms. The permitted values are 55-65 ohms.

HINT: Resistance will only be 60 ohms if the main artery of the CAN network is whole and the network is connected. If the main artery of the CAN network is split somewhere and a reading is taken between the CAN cables, resistance will be 120 ohms.

Also measure the resistance between each terminal and supply voltage and ground. The resistance must be infinite or very high (higher than 1 MOhm).

HINT: If a fault is found, try to disconnect the junction with the fault at a point further forward. Disconnect any connector/control module immediately before the measurement point and take the reading again. Try to locate the fault in this way.

Remedy the cables as necessary.

Other Information
- Battery, disconnecting
- See Checking Wiring and Terminals under Related Tests, Information and Procedures

Was a fault detected?

YES: Refer to Reading Off DTCs From All Systems Before Erasing. Reading Off DTCs From All Systems Before Erasing
NO: Refer to Checking the Traffic Load on the CAN Cables. Checking the Traffic Load on the CAN Cables