41TE NGC
P0890-SWITCHED BATTERY
Theory of Operation
The transmission control output circuit is used to supply power to the Solenoid/Pressure Switch Assembly and the PCM when in normal operating mode and to turn off power to those components when a transmission "limp-in" mode is requested. The transmission control output circuit is also referred to as "switched battery". After a controller reset (ignition turned to the run position or after cranking the engine), the controller verifies proper control of the transmission control output circuit by monitoring the presence of voltage in each of the solenoid pressure switches and the Transmission Control Output circuits at the controller when in the disabled mode.
- When Monitored:
One time after a reset (ignition turned to the RUN position or after cranking engine).
- Set Condition:
A fault is set if a detected voltage is greater than 4.5 volts for 7 msec on any of the pressure switch circuits before a request for the Transmission Control output circuit is turned on. If detected the transmission will be placed in Limp-In and illumination of the MIL after 10 seconds of vehicle operation and problem identification.
Always perform the 40/41TE Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure
1. CHECK IF DTC IS ACTIVE
1. With the scan tool, check 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
1. Turn the ignition off to the lock position.
2. Disconnect the PCM C4 harness connector.
3. 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 PCM Pinout Box 8815 to perform diagnosis.
4. Ignition on, engine not running.
5. With the scan tool in the TIPM, actuate the Transmission.
6. Ignition on, engine not running.
7. 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 TRANSMISSION VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Go To 3
3. (T47) 2/4 PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
NOTE: Continue actuating the Transmission.
1. 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 TRANSMISSION VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Go To 4
4. (T50) L/R PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE
NOTE: Continue actuating the Transmission.
1. 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 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. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. With the scan tool, perform QUICK LEARN Quick Learn Procedure.
- Perform 40/41TE TRANSMISSION VERIFICATION TEST 40/41TE Transmission Verification Test
5. INTERMITTENT 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 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 TRANSMISSION VERIFICATION TEST 40/41TE Transmission Verification Test
No
- Test Complete.