Taking Reading On Cables In The Can Network (LS-Can)
- Ignition off
- Disconnect the battery negative lead.NOTE:
- Remove the central electronic module (CEM)
- Connect the breakout box to the cable harness for the central electronic module (CEM). Do not connect the central electronic module (CEM).
HINT: Where a breakout box cannot be used, take readings from the rear of the affected connectors if possible. This prevents terminal pins and socket housings being damaged.
Disconnect the CAN network to make it easier to locate a fault. A suitable point to disconnect the network is at the central electronic module (CEM). Fault-tracing therefore starts from the central electronic module (CEM).
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 during each measurement to identify any intermittent short-circuits.
NOTE:The following resistance readings only measure the main arteries in the low speed network, not the junctions that exist for some control modules. If an open-circuit is suspected in a cable, or a short-circuit is suspected in one of its junctions, the connector at the control module for this junction must be disconnected and the reading taken from there.
Take the following readings
- Between terminals #F15 (#15) and #F30 (#30). Check the resistance. The resistance must be approximately 120 Ω.
- Between terminal #F15 (#15) and a terminal for supply voltage, and between terminal #F15 (#15) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ)
- Between terminal #F30 (#30) and a terminal for supply voltage, and between terminal #F30 (#30) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ).
- Between terminals #B8 (#8) and #B9 (#9). Check the resistance. The resistance must be approximately 120 Ω.
- Between terminal #B8 (#8) and a terminal for supply voltage, and between terminal #B8 (#8) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ)
- Between terminal #B9 (#9) and a terminal for supply voltage, and between terminal #B9 (#9) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ).
- Between terminals #B24 (#24) and #B25 (#25). Check the resistance. The resistance will be approximately 37 kΩ. The resistance must not be 0 Ω!NOTE:
The reading will only be obtained if a phone module (PHM) is installed. If a carphone is not installed, the resistance should be infinite.
- Between terminal #B24 (#24) and a terminal for supply voltage, and between terminal #B24 (#24) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ)
- Between terminal #B25 (#25) and a terminal for supply voltage, and between terminal #B25 (#25) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ).
- Between terminals #G16 (#16) and #G32 (#32). Check the resistance. The resistance will be approximately 37 kΩ. The resistance must not be 0 Ω!NOTE:
The reading will only be obtained if a combustion preheater module (CPM) is installed. If the engine coolant heater is not installed, the resistance must be infinite.
- Between terminal #G16 (#16) and a terminal for supply voltage, and between terminal #G16 (#16) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ)
- Between terminal #G32 (#32) and a terminal for supply voltage, and between terminal #G32 (#32) and a terminal for ground. Check the resistance. The resistance must be infinite or very high in both cases (higher than 1 MΩ).
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 as necessary.
Other information
Was a fault detected?
- YES
Refer to VERIFICATION
- NO