P0890
P0890-SWITCHED BATTERY
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The transmission output from the PDC 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 PDC 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 TCM relay is not energizing the output by checking for no voltage on Switched battery line (Transmission Control Output) before the relay is command to energize the output. After switched battery is verified for no voltage, the voltage of each of the solenoid 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 turned to the RUN position or after cranking engine).
- Set Condition:
A fault is set if the sensed voltage on any of the pressure switch circuits is greater than 4.5 volts for the period of 7 msec before a request by the Transmission Control System requests the Transmission Control Output circuit to be energized. The transmission is placed in Limp-In and the MIL is illuminated after 10 seconds of vehicle operation.
Always perform the 40/41TE Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. CHECK TO SEE IF DTC P0890 IS PRESENT
1. With the scan tool, read Transmission DTCs.
Is the status Active for this DTC or is the Starts Since Set counter set at 0?
Yes
- Go To 2
No
- Go To 6
2. CHECK TCM RELAY
1. Clear Transmission DTCs.
2. Turn the ignition off to the lock position.
3. Install known good TCM relay.
4. Ignition on, engine not running.
5. With the scan tool, read Transmission DTCs.
Is the status Active for this DTC or is the Starts Since Set counter set at 0?
Yes
- Go To 3
No
- Replace TCM relay.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
3. (T9) OD PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
1. Turn the ignition off to the lock position.
2. Disconnect the PCM C1 harness connector.
3. Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
4. Ignition on, engine not running.
5. Measure the voltage of the (T9) OD Pressure Signal circuit.
Is the voltage above 0.5 of a volt?
Yes
- Repair the (T9) OD Pressure Signal circuit for a short to voltage.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
No
- Go To 4
4. (T47) 2/4 PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
1. Measure the voltage of the (T47) 2/4 Pressure Signal circuit.
Is the voltage above 0.5 of a volt?
Yes
- Repair the (T47) 2/4 Pressure Signal circuit for a short to voltage.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
No
- Go To 5
5. (T50) L/R PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
1. Measure the voltage of the (T50) L/R Pressure Signal circuit.
Is the voltage above 0.5 of a volt?
Yes
- Repair the (T50) L/R Pressure Signal circuit for a short to voltage.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
No
- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the PCM. Service and Repair. With the scan tool, perform Quick Learn.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
6. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wiring and connectors while checking for shorted and open circuits.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the 40/41TE TRANSMISSION VERIFICATION TEST. 40/41TE Transmission Verification Test.
No
- Test Complete.