Circuit Description
The TAP Shift system allows the driver to manually shift gears by using the TAP Shift switches located on the Automatic Transmission shift lever. Pushing the upshift button will command an upshift and pushing the downshift switch will command a downshift. The TAP Shift system is activated when the gear selector is in the Low (L) position and is deactivated in all other positions.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Are DTCs P0815, P0816, P0826, P1876, or P1877 set? | -- | Go to Step 2 | |
2 |
Does the scan tool Driver Shift Control parameter display Inactive? | -- | Go to Step 3 | Go to Step 8 |
3 |
Does the scan tool Driver Shift Control parameter display Active? | -- | Go to Step 6 | Go to Step 4 |
4 | Using the J 39200 digital multimeter (DMM) and the J 35616 GM terminal test kit, measure the voltage between the TAP Up/TAP Down enable signal circuit and a known good ground at the AT shift lever connector. Does the voltage measure near the specified voltage? | 12 V | Go to Step 5 | Go to Step 9 |
5 | Using the J 39200 digital multimeter (DMM) and the J 35616 GM terminal test kit, measure the voltage between the TAP Up/TAP Down enable signal circuit and the TAP Up/TAP Down ground circuit at the AT shift lever connector. Does the voltage measure near the specified voltage? | 12 V | Go to Step 11 | Go to Step 10 |
6 |
Does the Driver Shift Request parameter display upshift? | -- | Go to Step 7 | Go to Step 11 |
7 | While observing the scan tool push the downshift switch on the AT shift lever. Does the Driver Shift Request parameter display downshift? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 11 |
8 | Test the driver shift control enable signal circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
9 | Test the driver shift control enable signal circuit for an open. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 | Test the driver shift control ground circuit for an open. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | -- |
11 | Replace the Floor Shift Control. Refer to Transmission Control Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
12 | Replace the Body Control Module. Refer to Control Module References for replacement, set-up, and programming. Did you complete the replacement? | -- | Go to Step 13 | -- |
13 | Perform the following procedure in order to verify the repair:
Do the Driver Shift Control and the Driver Shift Request parameters indicate the proper display? | -- | System OK | Go to Step 1 |
