Checking The Wiring And Components

Electronic throttle module (ETM) or Engine control module (ECM) does not work especially well together with CAN-high speed net. The two control modules monitor the CAN-high speed net continuously and are very sensitive to interference on the network. The two control modules will generate diagnostic trouble codes very quickly, if they detect problems on the network and will then reconfigure the system so that it is still possible to drive the vehicle, but then with reduced functionality. If Engine control module (ECM) or Electronic throttle module (ETM) detects a problem on the CAN-bus, this does not indicate that they have caused the interference. Most probable is that, since these control modules are the most sensitive on the CAN-high speed net, they will then also be the first that generate diagnostic trouble code when there is interference on the CAN-net.

As the information states, many of the CAN- and throttle module-related diagnostic trouble codes can be generated due to communication in the CAN-network has been interfered with or interrupted for some reason. Thus, the reconfiguration that takes place does not indicate the cause. Therefore, troubleshoot diagnostic trouble codes for the CAN-net first in all control modules, using troubleshooting for these.

S60/V70 (00-)/V70 XC (01-)/S80 (-06) 

HINT: If there are diagnostic trouble codes stored in central electronic module (CEM) that indicate incorrect communication in CAN-high speed net, troubleshoot according to these before the following troubleshooting is performed. If there are stored diagnostic trouble codes, this indicates that the problem has existed for a longer time, more than 5 seconds. However, if no diagnostic trouble codes are stored, then this indicates that the problem is of a brief nature, shorter time than 5 seconds, likely caused by very brief interference, open circuit or short-circuiting in leads or connections. 

If the VIDA-station with VCT2000 (Volvo Communication Tool 2000) is connected to the vehicle when the battery voltage is low, this may generate diagnostic trouble codes. VCT2000 receives voltage feed from the vehicle, and thus both VCT2000 and control modules can be interfered with and themselves generate interference when their feed voltages are low, (especially when trying to start and the battery is poorly charged). In certain cases, for troubleshooting of a CAN-related diagnostic trouble code, verify using counter and frozen values that the diagnostic trouble code is relevant and not stored during the time in the workshop.

Diagnostic trouble codes generated during troubleshooting can be identified using the frozen values and counters that are stored together with the diagnostic trouble code. Primarily driving distance is to be used to decide if the diagnostic trouble code is generated in the workshop or not. Compare the driving distance in frozen values with the driving distance in driver information module (DIM). If these do not differ too much, it is likely that the diagnostic trouble code was generated during the time that the vehicle was in the workshop. If the driving distance is 0 km/miles, this indicates that the problem has occurred at the control modules' start-up, when a correct driving distance not yet has been received from central electronic module (CEM) or Driver information module (DIM). In these cases, counter 5 can be used to determine when the problem was generated. This prevents fault-tracing an irrelevant code. The risk with too low system voltage in the vehicle can be minimized using a battery charger. In this way voltage is kept stable, if troubleshooting goes on for an extended period of time.

• Check the connector on the electronic throttle module (ETM). Check for contact resistance and oxidation. In particular, check terminals #3 (CAN H) and #4 (CAN L), #5 (ground) and #6 (voltage).
• Check the connector on the engine control module (ECM). Check for contact resistance and oxidation. In particular check terminals #A37 (#A37) (CAN H) and #A55 (#A55) (CAN L). In particular, check the wiring, pins and terminals for damage. Check that they are properly inserted into the connector. Check that the cable is properly connected to the pin or terminal.
• Check the CAN H cable between electronic throttle module (ETM) terminal #3 and engine control module (ECM) #A37 (#A37). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
• Check the CAN L cable between electronic throttle module (ETM) terminal #4 and engine control module (ECM) #A55 (#A55). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
• Check the voltage supply cable between electronic throttle module (ETM) terminal #6 and system relay terminal #3 (87). Check for an open-circuit.

  HINT: With the ignition on, the voltage must be approximately battery voltage between electronic throttle module (ETM) terminal #6 and ground. 

• Check the ground lead between electronic throttle module (ETM) terminal #5 and the car body. Check for an open-circuit. Check for a short-circuit to supply voltage.

If no fault is detected in the above fault-tracing, the fault may be because there was a delay before the system relay switched on. This delay may be due to low battery voltage and/or a mechanical fault in the system relay.

HINT: For markets where upgraded software, released during year 2006 or later, is available, the solution may be to download the upgraded software. In the upgraded software certain adjustments have been made to make it more tolerant against brief CAN-interference. See conditions for respective diagnostic trouble code, for more detailed information about what adjustments have been performed. 

Remedy as necessary.

Other information: 

• See Identifying upgraded software ECM/ETM
• See Checking wiring and terminals

Choose No to troubleshoot the whole CAN-net.

Was a fault detected? 

• YES 

  OKAY:  Troubleshooting has been completed.

• NO 

  Refer to Faulty Communication