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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

Typical Scan Tool Data






Circuit/System Description

When the 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 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 shift lever is placed in the M position, a corresponding voltage drop occurs across the resistor network, a voltage drop also occurs when the shift lever is pushed forward for an upshift, or the shift lever is pulled rearward for a downshift. Each voltage drop is monitored by the BCM. The BCM will send the request to the transmission control module to perform the upshift or downshift.

Conditions for Running the DTC

P0815, P0816, or P0826

* DTC P0815, P0816, P0826, P182E, P1876, P1877, P1915 or P1761 is not set.

* The ignition voltage is 8.6 volts or greater.

* The engine speed is 400 RPM or greater for 5 seconds.

P1876

* DTC U0100, P0815, P0816, P0826, P1825, P1876 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 TCM 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 inhibits Tap Up/Down function.

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 Fuel Pump and Level Sensor Assembly

* Inline Harness Connector End Views X100

Description and Operation

* Transmission General Description Transmission General Description

* Transmission Component and System Description Transmission Component and System Description

* Transmission Adaptive Functions Transmission Adaptive Functions

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. Ignition ON, observe the scan tool Driver Shift Control parameter, while moving the transmission shift through the park, reverse, neutral and drive positions. The parameter should display Inactive.

• If the parameter displays Active

Refer to Circuit/System Testing below.

• If the parameter displays Inactive

2. Shift lever in the M position, observe the scan tool Driver Shift Request parameter while pushing the shift lever forward and pulling the shift lever rearward. The parameter should change from None to Upshift or Downshift.

• If the parameter displays None

Refer to Circuit/System Testing below.

• If the parameter displays Upshift or Downshift

3. 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 the Circuit/System Verification first.

1. Ignition OFF, disconnect the automatic transmission shift lever harness connector from the shift lever assembly.

2. Test for less than 10 ohms between the shift lever harness connector terminal 3 and ground.

• If greater than the specified value

Repair the ground circuit.

• If less than the specified value

3. Ignition ON, verify with a scan tool the Driver Shift Control parameter displays Inactive.

• If the parameter displays Active

Test the signal circuit between shift lever assembly connector terminal 4 and the BCM for a short to voltage or ground. If the circuit tests normal, replace the BCM.

• If the parameter displays Inactive

4. Ignition OFF, connect a test lamp between shift lever harness connector B+ terminal 1 and ground circuit terminal 3.

5. Ignition ON, verify the test lamp is illuminated.

• If the test lamp is not illuminated

Test the B+ circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

• If the test lamp is illuminated

6. Test for 11-13 volts at the shift lever assembly harness connector between signal circuit terminal 4 and ground.

• 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 BCM.

• If the test lamp is illuminated

7. Ignition OFF, connect the shift lever harness connector.

8. Ignition ON, back probe the shift lever assembly connector and test for 11-13 volts between terminal 4 and ground with the shift lever in park, reverse, neutral, and drive.

• If not within the specified range

Replace the shift lever assembly.

• If within the specified range

9. Use a DMM to Monitor the voltage between shift lever assembly connector terminal 4 and ground with the shift selector in the M, tap up, and tap down position. Compare the readings and verify the voltages are correct for each position as follows:

* Manual: 2.7-3.1 volts

* Tap Up: 1.9-2.3 volts

* Tap Down: 1.16-1.56 volts

• If not within the specified range

Test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the shift lever assembly.

• If within the specified range

10. If all circuits test normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Refer to Control Module References Control Module References for BCM replacement, programming, and setup.

* Refer to Manual Shift Shaft Position Switch Replacement Service and Repair.

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