P0890-SWITCHED BATTERY





For a complete wiring diagram Refer to Section 8W.

Theory of Operation


The transmission relay 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 relay 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 relay contacts are open by checking for no voltage on Switched battery line (transmission control relay output) before the relay is energized. 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 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 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)



Diagnostic Test

1.CHECK TO SEE IF DTC P0890 IS PRESENT



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 SWITCH SENSE CIRCUIT SHORT TO VOLTAGE







NOTE: Check connectors - Clean/repair as necessary.



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.





Is the voltage above 0.5 volt?

Yes


No
  • Go To 3

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



NOTE: The jumper wire must still be in place.




Is the voltage above 0.5 volt?

Yes


No
  • Go To 4

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



NOTE: The jumper wire must still be in place.




Is the voltage above 0.5 volts?

Yes


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 the PCM per the Service Information. With the scan tool, perform QUICK LEARN
  • Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

5.INTERMITTENT WIRING AND CONNECTORS






Were there any problems found?

Yes


No
  • Test Complete.