P0890-SWITCHED BATTERY
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
The Totally Integrated Control Module (TIPM) replaces the Transmission control relay. The Transmission Control Output circuit is used to supply power to the solenoids and pressure switches (Transmission
Solenoid/TRS Assembly) when the transmission is in normal operating mode. When the Transmission Control Output circuit is off, no power is supplied and the transmission.
Immediately after a controller reset (ignition key turned to the "run" position or after cranking engine), the TCM verifies that the Transmission Control Output circuits are open by checking
for no voltage at the transmission control output terminals at the PCM. After this is verified, the voltage at the pressure switches are checked. There should be no voltage on the pressure switches at this
time. The PCM will then activate the relay.
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When Monitored:
When the ignition is turned from "OFF" position to "RUN" position and/or the ignition is turned from "START" position to "RUN" position.
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Set Condition:
This DTC is set if the Powertrain Control Module senses voltage on any of the pressure switch inputs prior to the Transmission Control Output circuit being energized.
Possible Causes
|
PRESSURE SWITCH SENSE CIRCUITS SHORT TO VOLTAGE
|
TRANSMISSION SOLENOID/TRS ASSEMBLY
|
POWERTRAIN CONTROL MODULE
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Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 45RFE/545RFE - STANDARD PROCEDURE)
Diagnostic Test
1.
CHECK FOR TIPM TCM DTCS
With the scan tool, read DTCs.
Are there any TCM Power Control DTCs present?
Yes
-
Refer to the Transmission category and perform the appropriate symptom.
No
2.
CHECK TO SEE IF DTC P0890 IS PRESENT
With the scan tool, Check the STARTS SINCE SET counter for P0890.
NOTE:
This counter only applies to the last DTC set.
Is the "Starts Since Set" counter set at 0?
Yes
No
3.
CHECK THE PRESSURE SWITCH SENSE CIRCUITS FOR A SHORT TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the PCM C4 harness connector and connect Miller tool #8815.
Disconnect the Transmission Solenoid/TRS 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
tool #8815 to perform diagnosis.
Ignition on, engine not running.
With the scan tool under TIPM, actuate the Transmission.
Measure the voltage of the (T147) 2C, (T48) 4C, (T50) LR, (T9) OD, and (T29) UD Pressure Switch Sense circuits in Miller tool #8815.
Is the voltage above 0.5 volt on any of the measured circuits?
Yes
No
4.
CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY
With the scan tool under TIPM, stop the Transmission actuation.
Turn the ignition off.
Reconnect the Transmission Solenoid/TRS Assembly harness connector.
Ignition on, engine not running.
Measure the voltage of the (T147) 2C, (T48) 4C, (T50) LR, (T9) OD, and (T29) UD Pressure Switch Sense circuits in Miller tool #8815.
Is the voltage above 0.5 volts on any of the sense circuits?
Yes
No
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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 45RFE/545RFE TRANSMISSION VERIFICATION TEST.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
5.
CHECK THE WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires 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.
Where there any problems found?
Yes
No