DTC P0815, P0816, or P0826
Diagnostic Instructions
DTC Descriptors
DTC P0815: Upshift Switch Circuit
DTC P0816: Downshift Switch Circuit
DTC P0826: Up and Down Shift Switch Circuit
Typical Scan Tool Data
Driver Shift Request
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Tap Up/Tap Down Switch Signal Circuit
|
Invalid
|
None
|
Invalid/None
|
Circuit/System Description
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 plus (+) button to change up or
minus (-) button to change down. 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, a voltage drop occurs across the resistor
network. When the plus or minus button is pushed, a corresponding
voltage drop occurs across the resistor network. This 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 or P0816
• |
The engine speed is greater than 400 RPM for
at least 5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
DTC P0815, P0816, P0826, P182E, P1761, P1876,
P1877, or P1915 is not set. |
• |
The time since the last gear range change is
greater than 1 second. |
P0826
• |
The engine speed is greater than 400 RPM for
at least 5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
DTC P0826 or P1761 is not set. |
Conditions for Setting the DTC
P0815 - Condition 1
The transmission control module (TCM) detects an upshift
request for 1 second with the gear shift lever in PARK, or
NEUTRAL.
P0815 - Condition 2
The TCM detects an upshift request for 10 minutes with the
gear lever in a forward range.
P0816 - Condition 1
The TCM detects a downshift request for 1 second with the
gear shift lever in PARK, or NEUTRAL.
P0816 - Condition 2
The TCM detects a downshift request for 10 minutes with the
gear shift lever in a forward range.
P0826
The 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. |
• |
The 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
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
Circuit/System Verification
- Ignition ON, observe the scan tool Driver Shift
Control Mode parameter while moving the transmission gear shift
lever through all the positions. The parameter should display
Inactive in the park, reverse, neutral and drive positions, and
Active in the M position.
- Gear shift lever in the M position, verify the
scan tool Driver Shift Request parameter changes from None to
Upshift when the plus button is pressed, and from none to Downshift
when the minus button is pressed.
- 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 .
Circuit/System Testing
- Ignition OFF, disconnect the harness connector from
the S3 transmission gear lever assembly.
- Test for less than 10 ohms between the S3
transmission gear lever harness connector terminal 2 and
ground.
⇒ |
If greater than the specified range, repair the
ground circuit. |
- Ignition ON, verify the scan tool Driver Shift Control
parameter displays inactive.
⇒ |
If not the expected results, test the signal
circuit between S3 gear 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. |
- Ignition OFF, connect a test lamp between the S3
transmission gear lever harness connector ignition circuit
terminal 1 and ground circuit terminal 2.
- Ignition ON, verify the test lamp is illuminated.
⇒ |
If the light stays off, test the ignition circuit
for an open/high resistance. If the circuit tests normal, replace
the K9 BCM. |
- Test for 11-13 volts at the S3 transmission gear
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 K9 BCM. |
- Ignition OFF, connect the S3 transmission gear lever
harness connector.
- Ignition ON, back probe the S3 transmission gear lever
assembly connector and test for 11-13 volts between
terminal 3 and ground with the gear lever in park, reverse,
neutral, and drive.
⇒ |
If not within the specified range, replace the S3
transmission gear lever assembly. |
- Use a DMM to monitor the voltage between S3
transmission gear lever assembly connector terminal 3 and
ground with the gear 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:
• |
Tap down: 5.1-7.3 volts |
⇒ |
If not within the specified range, test the signal
circuit for a short-circuit to ground or open/high resistance. If
the circuit tests normal, replace the S3 transmission gear lever
assembly. |
- If all circuits test normal, replace the K9 BCM.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|