40/41TE Automatic Transaxle (GPEC)
P0890-SWITCHED BATTERY
For a complete wiring diagram Consult Diagrams/Electrical.
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 (Transmission Control Output) 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 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. Testing and Inspection
Diagnostic Test
1. CHECK TO SEE IF DTC P0890 IS PRESENT
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 5
2. (T9) OD PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the PCM C2 harness connector.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
Ignition on, engine not running.
With the scan tool in the TIPM, actuate the Transmission.
Measure the voltage of the (T9) OD Pressure Signal circuit.
Is the voltage above 0.5 volt?
Yes
- Repair the (T9) OD Pressure Signal circuit for a short to voltage.
- Perform 40/41TE VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Go to 3
3. (T47) 2/4 PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
NOTE: Under TIPM, continue to actuate the Transmission.
Measure the voltage of the (T47) 2/4 Pressure Signal circuit.
Is the voltage above 0.5 volt?
Yes
- Repair the (T47) 2/4 Pressure Signal circuit for a short to voltage.
- Perform 40/41TE VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Go to 4
4. (T50) L/R PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
NOTE: Under TIPM, continue to actuate the Transmission.
Measure the voltage of the (T50) L/R Pressure Signal circuit.
Is the voltage above 0.5 volts?
Yes
- Repair the (T50) L/R Pressure Signal circuit for a short to voltage.
- Perform 40/41TE 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. With the scan tool, perform QUICK LEARN.
- Perform 40/41TE VERIFICATION TEST 40/41TE Transmission Verification Test
5. 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 40/41TE VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Test Complete.