P1876
DTC P1876
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P1876
- Up and Down Shift Enable Switch Circuit Low Voltage
Circuit/System Description
The TAP Shift system allows the driver to manually shift gears by using the TAP shift switches located on the automatic transmission shifter. Pushing the Up switch will command an upshift and pushing the Down switch will command a downshift. The TAP shift system is activated when the gear selector is in the L (M) position and is deactivated in all other positions.
If the transmission control module (TCM) detects TAP enable switch Active and the IMS switch does not indicate L (M), DTC P1876 sets. DTC P1876 is a type C DTC.
Conditions for Running the DTC
* DTC P0815, P0816, or P0826, P1825, P1915 or U0100 is not set.
* Engine speed is 400 RPM or greater for 5 seconds.
* Ignition voltage is 8.6 volts or greater.
Conditions for Setting the DTC
The Tap Up/Tap Down switch signal is Active when the IMS does not indicate L (M) for 2 seconds or greater 3 times during the same ignition cycle.
Action Taken When the DTC Sets
* DTC P1876 is a Type C DTC.
* TCM disables Tap shift functions.
Conditions for Clearing the DIC/DTC
DTC P1876 is a Type C DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
* Transmission General Description Transmission General Description
* Electronic Component Description Electronic Component Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
Warning: Refer to Parking Brake and Drive Wheels Warning Parking Brake and Drive Wheels Warning.
1. Verify there no transmission internal mode switch (IMS) DTCs set.
• If IMS DTCs were set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If IMS DTCs were not set
2. Ignition ON.
3. Verify the gear shift lever position matches the scan tool TCM Internal Mode Switch parameter while slowly moving the gear shift lever from Park through all ranges.
• If the displayed values are not correct
Refer to Range Selector Lever Cable Adjustment Adjustments
• If the displayed values are correct
4. Verify the scan tool Driver Shift Control Mode parameter displays Inactive with the transmission shift lever the Park, Reverse, Neutral, and Drive, and active in the M manual mode position.
• If the Driver Shift Mode parameter does not display the correct values
Refer to Circuit/System Testing below.
• If the Driver Shift Mode parameter displays the correct values
5. Shift lever in the M position, verify the scan tool Driver Shift Request parameter changes from None to Upshift when the plus button is pressed, and from None to Downshift when the minus button is pressed.
• If the Driver Shift Request parameter does not display the correct values
Refer to Circuit/System Testing below.
• If the Driver Shift Request parameter displays the correct values
6. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
Note: You must perform Circuit/System Verification first.
1. Ignition OFF, disconnect the harness connector from the S3 transmission shift lever.
2. Test for less than 10 ohms between the S3 transmission shift lever harness connector terminal 2 and ground.
• If greater than the specified range, repair the ground circuit.
3. Ignition ON.
4. Verify the scan tool Driver Shift Control parameter displays inactive.
• If Driver Shift Control Parameter does not display Inactive
Test signal circuit for a short to power or ground.
• If signal circuit has a short to voltage or ground, repair the circuit.
• If signal circuit does not have a short to voltage or ground, replace the K9 body control module.
• If Driver Shift Control Parameter displays Inactive
5. Verify a test lamp illuminates between the S3 transmission shift lever harness connector ignition circuit terminal 1 and ground circuit terminal 2.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the ignition circuit end to end.
• If 2 ohms or greater, repair the ignition circuit
• If less than 2 ohms, replace the K9 body control module
• If the test lamp illuminates
6. Test for 11 volts or greater at the S3 transmission shift lever harness connector between signal circuit terminal 3 and ground.
• If less than 11 volts
1. Ignition OFF.
2. Test for less than 2 ohms in the signal circuit wire end to end.
• If 2 ohms or greater, repair the open/high resistance in the signal circuit wire.
• If less than 2 ohms, replace the K9 body control module.
• If 11 volts or greater
7. Ignition OFF, connect the S3 transmission shift lever harness connector, ignition ON.
8. Test for 11 volts or greater between the S3 transmission shift lever connector terminal 3 and ground in the park, reverse, neutral, and drive gear select lever positions by back probing the connector.
• If less than 11 volts
Replace the S3 transmission shift lever.
• If 11 volts or greater
9. Test for 8.0-10.6 volts between the S3 transmission shift lever connector terminal 3 and ground with the shift lever in the M position.
• If not between 8.0-10.6 volts
Replace the S3 transmission shift lever.
• If between 8.0-10.6 volts
10. Test for 5.1-7.3 volts between the S3 transmission shift lever connector terminal 3 and ground with the shift lever in the M position and the tap up button pressed.
• If not between 5.1-7.3 volts
Replace the S3 transmission shift lever.
• If between 5.1-7.3 volts
11. Test for 2.0-4.6 volts between the S3 transmission shift lever connector terminal 3 and ground with the shift lever in the M position and the tap down button pressed.
• If not between 2.0-4.6 volts
Replace the S3 transmission shift lever.
• If between 2.0-4.6 volts
12. Replace the K9 body control module
Repair Instructions
Note:
* Perform the Reset Transmission Adapts Reset Transmission Adapts following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection.
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Transmission Control Replacement (Acadia) Transmission Control Replacement for AT TAP shift switch replacement.
* Control Module References Programming and Relearning for body control module (BCM) or control solenoid valve assembly replacement, setup, and programming