Use of Serial Data Link Diagnostic Communication Tools to Retrieve Mode 6 Data
| Subject: | Use of Serial Data Link Diagnostic Communication Tools to Retrieve Mode 6 Data (Request On-Board Monitoring Test Results by Test ID) |
| Models: | All 1996-1998 Saturn vehicles |
Purpose
Federal emission regulations require that a vehicle be able to display certain data when interrogated using an off-board tool. One group of data that must be displayed is Mode 6 Data. Within Mode 6 Data is a description of the EGR flow test results:
Test ID | $07 | Request EGR flow test results |
Comp ID | $0D | Request for deceleration test only |
Test Value | (0D) | Scaling of the test value is a 2's complement signed number: QEMDSTHR E=(N) counts (2 byte) |
Test Limit | (0D) | Scaling of the test value is a 2's complement signed number: QEMDSEWN E=(N) counts (2 byte) |
On all 1996-1998 Saturn vehicles, the EGR flow test results are incorrectly displayed in the reverse order. Instead of the test results being displayed Test Value first and Test Limit second, the Test Limit is displayed first and Test Value is displayed second. This must be taken into consideration when displaying Mode 6 Data or when developing communication tools that use Mode 6 Data communication.
Important: The preceding information only affect off-board diagnostic communication tools that use a Mode 6 Data request. The Saturn off-board diagnostic communication tools (Tech 2, PDT, and SSS) do not use Mode 6 Data to interrogate any vehicle data.
