P0815
DTC P0815, P0816, P0826, or 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 Descriptors
DTC P0815
-
Upshift Switch Circuit
DTC P0816
-
Downshift Switch Circuit
DTC P0826
-
Up and Down Shift Switch Circuit
DTC P1876
-
Up and Down Shift Enable Switch Circuit Low Voltage
Diagnostic Fault Information
Circuit/System Description
When the shift lever is placed in manual mode (M) this activates the drivers shift request (DSR), also known as the tap shift function. There are two plus (+) buttons and two minus (-) buttons. The two plus buttons are located on either side on top of the horizontal cross bar of the steering wheel. The two minus buttons are located on either side of the horizontal cross bar of the steering wheel facing the instrument cluster. The DSR allows the vehicle operator to shift gears by pressing the plus button for an upshift or the minus button for a downshift. An ignition voltage circuit is provided to the left and right automatic manual shift switches. A signal circuit from the left automatic transmission manual shift switch to the Transmission Control Module (TCM) completes the circuit. When a plus or minus button is pressed, a corresponding voltage drop occurs across the resistor network embedded in the left switch. The voltage drop is monitored by the TCM. When commanded the TCM will perform an upshift or downshift depending on the engine and transmission operating conditions.
Conditions for Running the DTC
P0815, P0816, P0826 or P1876
* DTC U0100, P0815, P0816, P0826, P1761, P182E, P1876, P1877, or P1915 is not set.
* The ignition voltage is 8.6 volts or greater.
* The engine speed is 400 RPM or greater for 5 seconds.
Conditions for Setting the DTC
P0815 - Condition 1
The BCM detects a stuck ON Tap Up switch for 1 second in Park or Neutral.
P0815 - Condition 2
The BCM detects a stuck ON Tap Up switch for 10 minutes in any forward gear.
P0816 - Condition 1
The BCM detects a stuck ON Tap Down switch for 1 second in Park or Neutral.
P0816 - Condition 2
The BCM detects a stuck ON Tap Down switch for 10 minutes in any forward gear.
P0826
The BCM detects an invalid voltage on the TAP up/down signal circuit for 1 minute.
P1876
The BCM detects a TAP Enable Switch request 3 times when not in M (D6) range for 2 seconds.
Action Taken When the DTC Sets
* DTCs P0815, P0816, P0826, and P1876 are Type C DTCs.
* The TCM disables TAP shift operation.
Conditions for Clearing the DTC
DTCs P0815, P0816, P0826, and P1876 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
* Component Connector End Views Folding Top 5 Bow Lowered Switch (CM7)
* Inline Harness Connector End Views X102
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System 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 Control Module References for scan tool information
Circuit/System Verification
1. Engine running, park brake applied, drive wheels chocked. Shift the transmission into the manual (M) position. Verify with a scan tool the following TCM parameters display the correct values:
* Drivers Shift Control - Inactive
* Drivers Shift Request - Inactive
• If the TCM parameters are incorrect
Refer to Circuit/System Testing below.
• If the TCM parameters are correct
2. Verify with a scan tool the following TCM parameters display the correct values when pressing the plus button. Perform this test on both plus switches:
* Drivers Shift Control - Active
* Drivers Shift Request - Upshift
• If the TCM parameters are incorrect
Refer to Circuit/System Testing below.
• If the TCM parameters are correct
3. Verify with a scan tool the following TCM parameters display the correct values when pressing the minus button. Perform this test on both minus switches:
* Drivers Shift Control - Active
* Drivers Shift Request - Downshift
• If the TCM parameters are incorrect
Refer to Circuit/System Testing below.
• If the TCM parameters are correct
4. 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
1. Ignition OFF, obtain access to the automatic transmission manual shift switch left and right electrical connectors. Refer to Manual Shift Auxiliary Position Switch Replacement - Steering Wheel Manual Shift Auxiliary Position Switch Replacement - Steering Wheel.
2. Ignition ON, test for 10-13 volts by backprobing terminal 3 on the manual shift switch-left and ground at the battery negative post.
• If less than the specified value
Test for a short to ground or an open/high resistance in the ignition voltage circuit. If the circuit tests normal, replace the BCM.
• If within the specified value
3. Ignition OFF, disconnect the automatic transmission manual shift switch-right electrical connector.
4. Ignition ON, test for 10-13 volts at terminal 2 on the manual shift switch-right harness connector and ground at the battery negative post.
• If less than the specified value
Test the ignition voltage circuit from the automatic transmission manual shift switch-left for a short to ground or an open/high resistance. If the circuit test normal, replace the automatic transmission manual shift switch-left.
• If within the specified value
5. Ignition OFF, test for infinite resistance between terminal 1 and terminal 2 on the manual shift switch-right, with the switch open.
• If less than the specified value
Replace the automatic transmission manual shift switch-right.
• If within the specified value
6. Test for less than 5 ohms between terminal 1 and terminal 2 with the plus switch closed on the manual shift switch-right.
• If greater than the specified value
Replace the automatic transmission manual shift switch-right.
• If less than the specified value
7. Test for infinite resistance between terminal 2 and terminal 3 on the manual shift switch-right with the switch open.
• If less than the specified value
Replace the automatic transmission manual shift switch-right.
• If the specified value
8. Test for less than 5 ohms between terminal 2 and terminal 3 with the minus switch closed on the manual shift switch-right.
• If greater than the specified value
Replace the automatic transmission manual shift switch-right.
• If less than the specified value
9. Ignition OFF, disconnect the automatic transmission manual shift switch-left electrical connector.
10. Test for 8.15-8.35 k ohms between terminal 3 and terminal 5 on the manual shift switch-left.
• If not within the specified range
Replace the automatic transmission manual shift switch-left.
• If within the specified range
11. Test for 4.27-4.57 k ohms between terminal 2 and terminal 5 with the plus switch closed on the manual shift switch-left.
• If not within the specified range
Replace the automatic transmission manual shift switch-left.
• If within the specified range
12. Test for 1.485-1.515 k ohms between terminal 2 and terminal 5 with the minus switch closed on the manual shift switch-left.
• If not within the specified range
Replace the automatic transmission manual shift switch-left.
• If within the specified range
13. Test for less than 5 ohms between terminal 1 and terminal 2 with the plus switch closed on manual shift switch-left.
• If greater than the specified value
Replace the automatic transmission manual shift switch-left.
• If less than the specified value
14. Test for less than 5 ohms between terminal 2 and terminal 4 with the minus switch closed on the manual shift switch-left.
• If greater than the specified value
Replace the automatic transmission manual shift switch-left.
• If less than the specified value
15. Ignition OFF, disconnect the X1 connector at the automatic transmission assembly.
16. Ignition OFF, connect a 3 A fused jumper wire between terminal 3 and terminal 5 at the automatic transmission manual shift switch-left.
17. Ignition ON, test for 10-13 volts at the harness connector X1 terminal 7.
• If not within the specified range
Test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TCM.
Repair Instructions
* Perform the Reset Transmission Adapts Reset Procedure following all transmission related repairs.
* Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Refer to Manual Shift Auxiliary Position Switch Replacement - Steering Wheel Manual Shift Auxiliary Position Switch Replacement - Steering Wheel for AT TAP shift switch replacement.
* Refer to Control Module References Control Module References for control solenoid valve assembly replacement, programming and setup.