P0815
DTC P0815, P0816, or P0826
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
Diagnostic Fault Information
Circuit/System Description
When the shift lever is placed in manual mode (M), electronic range select (ERS), which allows for the selection of the range of gears available, is activated. The ERS allows the vehicle operator to increase the highest range by pressing the plus (+) button or decrease the highest range by pressing the minus (-) button. The body control module (BCM) provides ignition voltage and a signal circuit to the resistor network embedded in the cruise control and tap shift switch assembly. When a plus or minus button is pressed, 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 (TCM) to increase or decrease the available gear ranges.
Conditions for Running the DTC
P0815 or P0816
* DTC P0815, P0816, P0826, P1761, P182E, P1876, P1877, or P1915 is not set.
* Time since the range change is greater than 1 second.
* Engine speed is 400 RPM or greater for 5 seconds.
* Ignition voltage is 8.6 volts or greater.
P0826
* Engine speed is greater than 400 RPM for at least 5 seconds.
* Ignition voltage is 8.6 volts or greater.
* DTC P0826 or 1761 is not set.
Conditions for Setting the DTC
P0815 - Condition 1
TCM detects an upshift request for 1 second in PARK or neutral.
P0815 - Condition 2
TCM detects an upshift request for 10 minutes in any forward range.
P0816 - Condition 1
TCM detects a downshift request for 1 second in PARK or neutral.
P0816 - Condition 2
TCM detects a downshift request for 10 minutes in any forward range.
P0826
TCM detects an invalid voltage on the Tap Up/Down signal circuit for 1 minute.
Action Taken When the DTC Sets
* DTCs P0815, P0816, and P0826 are Type C DTCs.
* TCM disables TAP shift operation.
Conditions for Clearing the DTC
DTCs P0815, P0816, and P0826 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
* Component Connector End Views A/C Compressor Clutch
* Inline Harness Connector End Views X101
Description and Operation
Transmission General Description Transmission General 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
Warning: Refer to Parking Brake and Drive Wheels Warning Parking Brake and Drive Wheels Warning.
1. Ignition ON, engine OFF, transmission shift lever in Park, parking brake ON.
2. Verify with a scan tool no 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
3. Transmission shift lever in manual mode (M).
4. Verify the scan the scan tool Driver Shift Request parameter displays None. Press and release the Tap Up (+) switch, and the Tap Down (-) switch. The parameter should change from None to Upshift when the Tap Up switch is pressed, and from None to Downshift when the Tap Down switch is pressed.
• If parameter does not display the correct values
Refer to Circuit/System testing below.
• If parameter displays the correct values
5. 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, parking brake ON, disconnect the steering wheel control switch - left connector, ignition ON.
2. Verify that a test lamp illuminates between the Steering Wheel Control Switch - Right connector ignition circuit terminal 1 and ground.
• If the test lamp does not illuminate
1. Ignition OFF, remove the harness connector from the K9 body control module.
2. Test for infinite resistance between the steering wheel control switch - left harness connector ignition circuit terminal 1 and ground.
• If less than infinite resistance, repair the short to ground in the circuit
• If infinite resistance
3. Test for less than 5 ohms in the ignition circuit end to end.
• If 5 ohms or greater, repair the open/high resistance in the circuit
• If less than 5 ohms, replace the K9 body control module.
• If the test lamp illuminates
3. Ignition OFF.
4. Test for 6.5-7.1 k ohms between the steering wheel control switch - left connector terminals 1 and 5. Verify the resistance changes to 1.7-2.1 k ohms when the Tap Up button is pressed and 3.8-4.2 k ohms when the Tap Down button is pressed.
• If not the correct values
Replace the cruise control and tap shift witch assembly.
• If values are correct
5. Remove the harness connector at the K9 body control module.
6. Test for infinite resistance between the steering wheel control switch - left harness connector signal circuit terminal 5 and ground.
• If less than infinite resistance
Repair the short to ground in the circuit
• If infinite resistance
7. Test for less than 5 ohms in the signal circuit end to end.
• If 5 ohms or greater
Repair the open/high resistance in the circuit.
• If less than 5 ohms
8. 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.
* Control Module References Control Module References for BCM or control solenoid valve assembly replacement, setup and programming
* Transmission Control Replacement Transmission Control Replacement