Circuit Description
WARNING: This page is about a different car, the 2005 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
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 shifter handle forward will command an upshift and pulling the shifter handle back will command a downshift. The TAP Shift system is activated when the gear selector is in the manual, M, position and is deactivated in all other positions.
TAP Shift Circuit Performance
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 |
|
- | Go to Diagnostic Trouble Code (DTC) List/Type | Go to Step 2 |
| 2 |
|
- | Go to Step 3 | Go to Step 8 |
| 3 |
|
- | 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 |
|
- | Go to Step 7 | Go to Step 11 |
| 7 | While observing the scan tool move the AT shift lever in the downshift position. Does the Driver Shift Request parameter display downshift? |
- | Go to Intermittent Conditions in Engine Controls-3.6L or Intermittent Conditions in Engine Controls - 4.6L | Go to Step 11 |
| 8 | Test the TAP Up/TAP Down enable signal circuit for a short to ground. Refer to Testing for Short to Ground
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 13 | Go to Step 12 |
| 9 | Test the TAP Up/TAP Down enable signal circuit for an open. Refer to Testing for Continuity
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 13 | Go to Step 12 |
| 10 | Test the TAP Up/TAP Down enable ground circuit for an open. Refer to Testing for Continuity
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 13 | - |
| 11 | Replace the Floor Shift Control. Refer to Floor Shift Control Replacement
. Did you complete the replacement? |
- | Go to Step 13 | - |
| 12 | Replace the Instrument Panel Cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement
in Instrument Panel, Gages and Console. 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 |