Limitations

Terminal "E" of the underdash ALCL connector allows access to a variety of ECM sensor circuit information, using several types of aftermarket scanners. Understanding what the function of the circuit involved is can be useful in obtaining information that might otherwise prove time consuming or impossible to obtain using other test procedures.

Serial Data access can be useful in obtaining information regarding intermittent malfunctions, as the tool can be installed and monitored while operating the vehicle under the conditions where the malfunction was reported to occur. If the malfunctions seem to be related to specific functions that are monitored by the access tool, the system can be checked in the applicable positions, under actual operating conditions. If the malfunction is not related to any specific area, the system can be monitored in all tester positions for a period of time or under a group of operating conditions. This allows the technician to observe the system and monitor changes in tester readings that may indicate a system malfunction.

For complete information regarding the operation of access tools and their affect on this system, refer to tester manufacturer's instructions.