P0890
P0890 - Switched Battery
For a complete wiring diagram, refer to.
Theory of Operation
The transmission output from the TIPM is used to supply power to the solenoid pack when in normal operating mode and to turn off power to produce transmission "limp-in" mode. The TIPM transmission output (which supplies power to the solenoid pack) is fed back to the controller. It is referred to as SWITCHED BATTERY. After a controller reset (ignition key turned to the RUN position or after cranking engine), the controller verifies that the TIPM is not energizing the output by checking for no voltage on switched battery line (TCM power input) before the command is sent to the TIPM to energize the output. After switched battery is verified for no voltage, the voltage of each of the solenoid pack pressure switches is also checked. Since the solenoid pack is not powered up, there should be no voltage on any of the pressure switches.
• When Monitored: One time after a reset (ignition key turned to the RUN position or after cranking engine).
• Set Condition: A fault is set if voltage greater than 4.5 volts is detected for 7 ms on any of the pressure switch circuits before the relay is energized. The transmission is placed in Limp-In. The MIL is on after 10 seconds of vehicle operation.
Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - Determine if DTC P0890 is present
• With the scan tool, view DTCs.
Is the status active for this DTC or is the STARTS SINCE SET counter set at 0?
Yes
• Go to Test Step 2.
No
• Go to Test Step 7.
Test Step 2 - OD Pressure Signal Circuit Short to Voltage
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
• Turn the ignition OFF to the lock position.
• Disconnect the PCM C4 harness connector.
• Disconnect the transmission solenoid/TRS assembly harness connector.
• Ignition ON, engine not running.
• With the scan tool in the TIPM, actuate the TCM output.
• Measure the voltage of the OD pressure signal circuit.
Is the voltage more than 0.5 volt?
Yes
• Repair the OD pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 3.
Test Step 3 - 2/4 Pressure Signal Circuit Short to Voltage
• Measure the voltage of the 2/4 pressure signal circuit.
Is the voltage more than 0.5 volt?
Yes
• Repair the 2/4 pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 4.
Test Step 4 - L/R Pressure Signal Circuit Short to Voltage
• Measure the voltage of the L/R pressure signal circuit.
Is the voltage more than 0.5 volts?
Yes
• Repair the L/R pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 5.
Test Step 5 - DC Pressure Signal Circuit Short to Voltage
• Measure the voltage of the DC pressure signal circuit.
Is the voltage more than 0.5 volts?
Yes
• Repair the DC pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 6.
Test Step 6 - LC Pressure Signal Circuit Short to Voltage
• Measure the voltage of the LC pressure signal circuit.
Is the voltage more than 0.5 volts?
Yes
• Repair the LC pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits. Replace and program the powertrain control module. Refer to With the scan tool perform Quick Learn.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
Test Step 7 - Intermittent Wiring and Connectors
• The conditions necessary to set the DTC are not present at this time.
• Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
• Wiggle the wiring and connectors while checking for shorted and open circuits.
• With the scan tool, check the DTC event data to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
• Repair as necessary.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Test Complete.