Circuit Description
The TAP Shift system allows the driver to manually shift gears by using the TAP Shift switches located on the steering wheel. Pushing either TAP Shift switch will command an upshift and pulling the switch 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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic Systems Check Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 3.8L |
2 |
Is DTC P0815, P0816 or P0826 set? | -- | Go to Step 3 | |
3 |
Does the scan tool Driver Shift Request parameter display upshift in the upshift position and downshift in the downshift position? | -- | Go to Step 4 | Go to Step 13 |
4 | Operate the Right Tap Shift switch in the upshift and downshift positions. Does the scan tool Driver Shift Request parameter display upshift in the upshift position and downshift in the downshift position? | -- | Go to Intermittent Conditions in Engine Controls - 3.8L | Go to Step 5 |
5 | Does the Driver Shift Request parameter display upshift in the upshift position? | -- | Go to Step 7 | Go to Step 6 |
6 | Does the Driver Shift Request parameter display downshift in the downshift position? | -- | Go to Step 9 | Go to Step 11 |
7 |
Caution: Refer to SIR Caution in the Preface section. Using the J 39200 digital multimeter (DMM) and the J 35616 GM terminal test kit, measure the resistance between terminals 1 and 3 of the Left TAP Shift switch. Refer to Testing for Continuity in Wiring Systems. Does the resistance measure within the specified range? | 1.47-1.53K ohms | Go to Step 8 | Go to Step 13 |
8 | Test the Downshift Request circuit for an open between the Left and Right Tap switches. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
9 |
Caution: Refer to SIR Caution in the Preface section. Using the digital multimeter (DMM) and the GM terminal test kit, measure the resistance between terminals 3 and 5 of the Left TAP Shift switch. Refer to Testing for Continuity in Wiring Systems. Does the resistance measure within the specified range? | 4.34-4.50K ohms | Go to Step 10 | Go to Step 13 |
10 | Test the Upshift Request circuit for an open between the Left and Right Tap switches. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
11 |
Caution: Refer to SIR Caution in the Preface section. Using the digital multimeter (DMM) and the GM terminal test kit, measure the resistance between terminals 2 and 4 of the Left TAP Shift switch. Refer to Testing for Continuity in Wiring Systems. Does the resistance measure greater than the specified value? | 10 ohms | Go to Step 13 | Go to Step 12 |
12 | Test the Ignition 1 voltage circuit for an open between the Left and Right Tap switches. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 | Replace the Left TAP Shift switch. Refer to Automatic Transmission Manual Shift Auxiliary Position Switch Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the Right TAP Shift switch. Refer to Automatic Transmission Manual Shift Auxiliary Position Switch Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 | Perform the following procedure in order to verify the repair:
Does the scan tool Driver Shift Request parameter display upshift in the upshift position and downshift in the downshift position for both TAP shift switches? | -- | System OK | Go to Step 1 |
