P0890

P0890-SWITCHED BATTERY

Wiring Diagram:

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 msec 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.

Possible Causes
- (T47) 2/4 PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
- (T50) L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
- (T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
- POWERTRAIN CONTROL MODULE

Always perform the 40/41TE Pre-Diagnostic Troubleshooting procedure before proceeding.

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.

Diagnostic Test
1. CHECK TO SEE 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 2.
No >> Go To 6.





2. (T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the PCM C4 harness connector.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.

CAUTION: 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.

Ignition on, engine not running.
With the scan tool in the TIPM, actuate the TCM output. Ignition on, engine not running.
Measure the voltage of the (T9) OD Pressure Switch Sense circuit.
Is the voltage above 0.5 volt?
Yes >> Repair the (T9) OD Pressure Switch Sense circuit for a short to voltage.
Perform 40/41TE VERIFICATION TEST - VER 1 Transmission Verification Test
No >> Go To 3.





3. (T47) 2/4 PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE

NOTE: The jumper wire must still be in place.

Measure the voltage of the (T47) 2/4 Pressure Switch Sense circuit.
Is the voltage above 0.5 volt?
Yes >> Repair the (T47) 2/4 Pressure Switch Sense circuit for a short to voltage.
Perform 40/41TE VERIFICATION TEST - VER 1 Transmission Verification Test
No >> Go To 4.





4. (T50) L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE

NOTE: The jumper wire must still be in place.

Measure the voltage of the (T50) L/R Pressure Switch Sense circuit.
Is the voltage above 0.5 volts?
Yes >> Repair the (T50) L/R Pressure Switch Sense circuit for a short to voltage.
Perform 40/41TE VERIFICATION TEST - VER 1 Transmission Verification Test
No >> Go To 5
5. POWERTRAIN CONTROL MODULE
Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary Pay particular attention to all power and ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace the Powertrain Control Module. With the scan tool perform QUICK LEARN.
Perform 40/41TE VERIFICATION TEST - VER 1 Transmission Verification Test
6. 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 - VER 1 Transmission Verification Test
No >> Test Complete.