P083A

P083A-LC HYDRAULIC PRESSURE TEST





For a complete wiring diagram Consult Diagrams/Electrical.

Theory of Operation

Pressure switches are normally open (off or no pressure applied) and read high (+12 volts). When an element is applied, the corresponding pressure switch closes to ground (0.0 volts) or turns on. The controller tests the LC pressure switch when it is open (when the corresponding friction element is not applied) by briefly applying the LC element which will cause the corresponding pressure switch to close. The test verifies that the switches are operational and that the switch will close when the corresponding element is applied. If a switch fails to respond to two consecutive tests, the transmission system defaults to limp-in mode and illuminates the MIL.

- When Monitored:
In any forward gear with engine speed above 1000 rpm, shortly after a shift and every minute thereafter.

- Set Condition:
After a shift into a forward gear, with engine speed greater than 1000 rpm, the PCM momentarily turns on element pressure to the clutch circuits that don't have pressure to verify that the correct pressure switch closes. If the pressure switch does not close 2 times the DTC will set.





Always perform the 62TE Pre-Diagnostic Troubleshooting procedure before proceeding.Testing and Inspection

Diagnostic Test

1. CHECKING FOR LOSS OF PRIME DTC
With the scan tool, check for other DTCs.
Is the DTC P0944 present also?

Yes

- Diagnose and repair the DTC(s).

No

- Go to 2

2. CHECK FOR RELATED TRANSMISSION DTCS
With the scan tool, check for other DTCs.
Are any of the DTCs P0731, P0733, P0734 and/or P083B present also?

Yes

- Replace the Transmission Solenoid/TRS Assembly.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Go to 3

3. CHECK TO SEE IF DTC P083A IS CURRENT
With the scan tool, read DTCs.
Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?

Yes

- Go to 4

No

- Go to 9

4. PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.

CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being started in gear.

WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in personal injury or death.

Install the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit.

NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector switch to LC.
With the scan tool, monitor the LC Pressure Switch state while pressing the Pressure Switch Test button on the Transmission Simulator.
Wiggle the wires leading to the PCM while pressing and holding the Pressure Switch Test button.
Did the LC Pressure Switch state change to closed and remain closed while wiggling the wires?

Yes

- Disassemble and inspect the Valve Body and repair or replace as necessary. If no problems are found in the Valve Body, replace the Transmission Solenoid/TRS Assembly.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Go to 5

5. (T81) LC PRESSURE SIGNAL CIRCUIT OPEN




Turn the ignition off to the lock position.
Disconnect the PCM C4 harness connector.
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 Special Tool #8815 to perform diagnosis.

Measure the resistance of the (T81) LC Pressure Switch Sense circuit from the appropriate terminal of Miller tool #8815 to the Transmission Solenoid/TRS Assembly harness connector.
Is the resistance above 5.0 ohms?

Yes

- Repair the (T81) LC Pressure Switch Sense circuit for an open.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Go to 6

6. (T81) LC PRESSURE SIGNAL CIRCUIT SHORT TO GROUND




Measure the resistance between ground and the (T81) LC Pressure Switch Sense circuit.
Is the resistance below 5.0 ohms?

Yes

- Repair the (T81) LC Pressure Switch Sense circuit for a short to ground.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Go to 7

7. (T81) LC PRESSURE SIGNAL CIRCUIT SHORT TO VOLTAGE




Ignition on, engine not running.
With the scan tool in the TIPM, actuate the TCM output.
Measure the voltage of the (T81) LC Pressure Switch Sense circuit.
Is the voltage above 0.5 volts?

Yes

- Repair the (T81) LC Pressure Switch Sense circuit for a short to voltage.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Go to 8

8. (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT OPEN




While still actuating the TCM output in the TIPM and using a 12-volt test light connected to ground, check (T16) Transmission Control Output circuit in the Transmission Solenoid/TRS Assembly harness connector.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- 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.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Repair the (T16) Transmission Control Output circuit for an open or high resistance. If the fuse is open make sure to check for a short to ground.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

9. 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 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.
Were there any problems found?

Yes

- Repair as necessary.
- Perform 62TE VERIFICATION TEST Transmission Verification Test

No

- Test Complete.