XC90 FWD L6-3.2L VIN 98 B6324S (2007)
In the event of difficulty, check as follows: Measure the supply voltage and ground terminal in the connector directly adjacent to the control module that
has stored the diagnostic trouble code (DTC).
Note! The terminals could be damaged when if readings are taken using measurement cables directly in the connector. If possible, take readings
on the rear of the connector. If this is not possible, use a loose terminal strip to insert in the connector.
Diagnostic testing of main arteries in the low speed network (LS-CAN)
Measure resistance between the CAN cables in the contact of the power seat module (PSM) if the vehicle is equipped with such (easily accessible).
Otherwise, connect a breakout box at the central electronic module (CEM) or at the driver information module (DIM). The advantage of using a
breakout box is that one can check the functionality of the entire network with all control modules connected.
This resistance measurement only checks the main arteries of the LS-CAN, not the branches (such as to the road traffic information module (RTI),
accessory electronic module (AEM), power seat module (PSM), phone module (PHM), audio module (AUM), driver door module (DDM), or passenger
door module (PDM). For further information see Service Manual, Wiring Diagram, Data Communication). Measuring resistance between the two CAN
cables can, however, indicate if there is a short-circuit between the two cables, including along a branch. A normal value measured near the middle of the
network lies between 55 and 65 ohms with all control modules connected (120 ohms connected in parallel). Twist and bend the cable harness at suitable
spots to detect any intermittent fault sources.
Also take resistance readings between each CAN cable and the supply voltage and ground. Twist and bend the cable harness at suitable points to detect
any intermittent fault causes. The resistance must be infinite or very high (higher than 1 MOhms).
Note! Resistance 60 ohms can only be measured if the main artery is intact and connected in the part of the CAN network in which the reading
is taken. If there is an open circuit anywhere along the main artery or if any control module through which the main artery passes (a control
module with four CAN connections) is not connected, resistance will be 120 ohms when the reading is taken. For more information, see the
wiring diagram.
Hint: Both readings can be taken in the same connector if the CAN cables, power supply and ground are exposed. If possible, take readings on the rear
of the connector to prevent damage to the terminals in the connector. If this is not possible, use the adapter wiring or loose terminal pins to obtain a good
contact. The resistance must be infinite or very high (higher than 1 MOhms).
If the main artery is OK (i.e. approximately 60 ohms measured in the power seat module (PSM), for example), measure the resistance in the CAN cables
from the relevant control module.
Diagnostic testing of main arteries in the high speed network (HS-CAN)
In principle it is only possible to measure the resistance in the high speed network (HS-CAN) using adapter wiring. It is easiest to connect the adapter
wiring at the engine control module (ECM). Connect the engine control module (ECM) again to the adapter wiring to obtain the correct values when
taking readings. The resistance must be approximately 60 ohms.
Note! Resistance 60 ohms can only be measured if the main artery is intact and connected in the part of the CAN network in which the reading
is taken. If there is an open circuit anywhere along the main artery or if any control module through which the main artery passes (a control
module with four CAN connections) is not connected, resistance will be 120 ohms when the reading is taken. For more information, see the
wiring diagram.
Abbreviations and terms
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LS-CAN. Low speed network in the car. In practice this is restricted to the passenger compartment and the cargo compartment
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HS-CAN. High speed network in the car. In practice this is restricted to the engine compartment.
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CAN-H. CAN cable with higher voltage; the voltage fluctuates between 2.5 and approx. 3.5 V when there is traffic on the CAN network.
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CAN-L. CAN network with lower voltage; the voltage fluctuates between 1.5 and 2.5 V when there is traffic on the CAN network.
