PRE-RELEASE
DTC P1876
| DTC P1876 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| 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 |
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No TAP system DTCs P0815, P0816, or P0826.
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No IMS DTCs P1825 or P1915.
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No Communication DTC U0100.
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The engine speed is greater than 500 RPM for 5 seconds.
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The ignition voltage is between 8.6 volts and 19.0 volts.
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| 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 |
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DTC P1876 is a Type C DTC.
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The TCM disables Tap shift functions.
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| Conditions for Clearing the DIC/DTC |
DTC P1876 is a Type C DTC.
| Reference Information |
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
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Transmission General Description
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Electronic Component Description
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Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| 1. |
Verify there are no IMS DTCs set.
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| 2. |
If IMS DTCs are set, diagnose them first.
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| 3. |
Ignition ON, transmission in Park, observe the scan tool Driver Shift Control parameter. The reading should display Inactive.
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| 4. |
After you complete the steps described above, check the diagnostic trouble code is not reset by driving the vehicle according to the conditions for running diagnostic trouble codes (DTC). You can also drive the vehicle according to the conditions you see in Freeze Frame/ Failure records. If the vehicle passes the circuit/system verification procedure, then stop. Do not perform the circuit/system test or component test as this may result in unnecessary part replacement. Refer to
Testing for Intermittent Conditions and Poor Connections
.
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| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the harness connector from the S3 transmission shift lever.
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| 2. |
Test for less than 10 ohms between the S3 transmission shift lever harness connector terminal 2 and ground.
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| 3. |
If greater than the specified range, repair the ground circuit.
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Ignition ON, verify the scan tool Driver Shift Control parameter displays inactive.
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| 5. |
If not the expected results, test the signal circuit between S3 shift lever assembly connector terminal 3 and the K9 BCM for a short to voltage or ground. If the circuit tests normal, replace the K9 BCM.
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| 6. |
Connect a test lamp between the S3 transmission shift lever harness connector ignition circuit terminal 1 and ground circuit terminal 2. Verify the test lamp is illuminated.
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If the light stays OFF, test the ignition circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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Test for 11-13 volts at the S3 transmission shift lever assembly harness connector between signal circuit terminal 3 and ground.
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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 K9 BCM.
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Ignition OFF, connect the S3 transmission shift lever harness connector.
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| 11. |
Ignition ON, back probe the S3 transmission shift lever assembly connector and test for 11-13 volts between terminal 3 and ground with the shift lever in Park, Reverse, Neutral, and Drive.
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If not within the specified range, replace the S3 transmission shift lever assembly.
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Monitor the voltage between S3 transmission shift lever assembly connector terminal 3 and ground with the shift lever in the M position, M position with the tap up plus button depressed, and the M position with the tap down minus button depressed. Compare the readings and verify the voltages are correct for each position as follows:
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Manual: 8.0-10.6 volts
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Tap down: 5.1-7.3 volts
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Tap up: 2.0-4.6 volts
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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 S3 transmission shift lever assembly.
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| 15. |
If all circuits test normal, replace the K9 BCM.
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| Repair Instructions |
| Note | ||
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Perform the
Resetting of the transmission's adaption
after all transmission repairs.
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Before replacing the TCM, perform the
Control Solenoid Valve and Transmission Control Module Assembly Inspection
.
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Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Transmission Control Replacement
for AT TAP shift switch replacement.
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Control Module References
for body control module (BCM) or control solenoid valve assembly replacement, setup, and programming
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