Cruze

DTC P1876

When the gear shift lever is placed in manual mode (M), the driver shift request (DSR), also known as the tap shift function, is activated. The DSR allows the vehicle operator to shift gears by pushing the shift lever forward for an upshift or pulling the shift lever rearward for a downshift. The body control module (BCM) supplies battery voltage, ground, and a signal circuit to the shift controller. The shift controller has Hall-effect switches connected to a resistor array. When the lever is in the M position, then pushed forward for an upshift, or pulled rearward for a downshift, a corresponding voltage drop occurs across the resistor network. This voltage drop is monitored by the BCM. The BCM sends the request to the transmission control module to perform the upshift or downshift.

The TCM detects a TAP Enable Switch request for 3 seconds when the transmission shift lever is in Park, Neutral, or Reverse, a total of 5 times.

DTC P1876 is a Type C DTC.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Note: If other DTCs are set, diagnose those DTCs first.

1. Ignition ON, observe the scan tool Driver Shift Control parameter in park, reverse, and neutral. The reading should display Inactive.
2. 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 .

Note: You must perform the Circuit/System Verification first.

1. Ignition ON, verify the scan tool IMS A/B/C/P parameter matches the Transmission Internal Mode Switch Logic in park, reverse, neutral and drive.

⇒	If not the expected results, refer to Shift Indicator Indicates Wrong Gear Selection .

2. Ignition OFF, disconnect the gear shift lever assembly electrical connector from the gear shift lever assembly.
3. Test for less than 10 ohms between the gear shift lever harness connector terminal 2 and ground.

⇒	If greater than the specified range, repair the ground circuit.

4. Ignition ON, verify the scan tool Driver Shift Control parameter displays inactive.

⇒	If not the expected results, test the signal circuit between gear shift lever assembly connector terminal 3 and the BCM for a short-circuit to voltage or ground. If the circuit tests normal, replace the BCM.

5. Ignition OFF, connect a test lamp between shift lever harness connector B+ circuit terminal 1 and ground circuit terminal 2.
6. Ignition ON, verify the test lamp is illuminated.

⇒	If the light stays off, test the B+ circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

7. Test for 11-13 volts at the gear shift lever assembly harness connector between signal circuit terminal 3 and ground.

⇒	If not within the specified range, test the signal circuit for a short-circuit to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

8. Ignition OFF, connect the gear shift lever harness connector.
9. Ignition ON, back probe the shift lever assembly connector and test for 11-13 volts between terminal 3 and ground with the shift lever in park, reverse, and neutral.

⇒	If not within the specified range, replace the gear shift lever assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Note: