P1776
P1776 - Solenoid Switch Valve Latched in LR Position
For a complete wiring diagram, refer to.
Theory of Operation
The solenoid switch valve, an internal, hydraulically operated valve, controls the direction of the transmission fluid when the L/R solenoid is energized. When the solenoid switch valve is in the downshifted position and the L/R solenoid is energized, fluid is directed to the L/R element for 1st gear. When the solenoid switch valve is In the up-shifted position (2nd, 3rd, and 4th gear) and the L/R solenoid is energized, fluid is directed into the lockup switch valve which controls the torque converter clutch. When doing PEMCC or FEMCC, the L/R pressure switch should indicate no pressure if the solenoid switch valve is in the L/R position. If the L/R pressure switch indicates pressure for some time while in partial or full EMCC, the EMCC operation is aborted and momentarily inhibited to avoid accidental application of the L/R clutch. EMCC is attempted again when there is no L/R pressure. The fourth detection of L/R pressure while in PEMCC or FEMCC will result in setting the DTC. Torque converter EMCC operation inhibited. MIL on after 5 min. of substituted operation.
• When Monitored: Every 7 ms when doing PEMCC or FEMCC.
• Set Condition: Must be in partial or full EMCC. The DTC is set if L/R pressure is detected high for the fourth time.
Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - Determining if Related DTCs are Present
• With the scan tool, check DTCs
Is the DTC P0841 present also?
Yes
• Refer to the transmission category and perform the appropriate diagnostic procedures.
No
• Go to Test Step 2.
Test Step 2 - Check the DTC Event Data for TRS Code TR2
• With the scan tool, check the DTC event data for P1776.
Does the DTC event data show a TRS Code of TR2?
Yes
• This indicates the shift lever and the manual control valve were in an invalid position between Neutral and OD. Check the shifter cable for: proper adjustment, binding, friction, improper routing, or the shifter was moved in transit. Repair as necessary.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 3.
Test Step 3 - Determine if DTC P1776 is Current
• With the scan tool, check the STARTS SINCE SET counter for P1776.
• This counter only applies to the last DTC set.
Is the status active or is the STARTS SINCE SET counter 2 or less for this DTC?
Yes
• Go to Test Step 4.
No
• Go to Test Step 9.
Test Step 4 - Check the PCM and Wiring with the Transmission Simulator
The starter solenoid relay must be removed from the TIPM. Failure to do so can result in personal injury or death.
Removal of the starter solenoid relay from the TIPM will prevent the vehicle from being started in gear.
• Turn the ignition OFF to the lock position.
• Remove the starter solenoid relay from the TIPM.
• Check connectors - Clean/repair as necessary.
• Install the transmission simulator, Miller tool #8333 and the electronic transmission adapter kit.
• Ignition ON, engine not running.
• With the transmission simulator, turn the pressure switch selector switch to L/R.
• With the scan tool, monitor the L/R pressure switch state while pressing the pressure switch test button.
Did the pressure switch state change from open to closed when the test button was pressed?
Yes
• Go to Test Step 5.
No
• Go to Test Step 6.
Test Step 5 - Check the Solenoid Switch Valve for Sticking
• Remove the transmission oil pan and valve body and inspect the solenoid switch valve for sticking in its bore, repair or replace as necessary.
• This DTC may be caused by debris lodged in the transmission solenoid switch valve bore. If debris is found, clean the valve body and reassemble the transmission.
• With the scan tool, record the DTC event data for P1776 and erase DTCs.
• Reassemble the transmission and test drive the vehicle. Try to duplicate the original set conditions using the DTC event data recorded earlier.
• With the scan tool, check Transmission DTCs.
Did the DTC P1776 reset?
Yes
• Replace the transmission solenoid/TRS assembly.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Test Complete
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
Test Step 6 - Check the L/R Pressure Signal Circuit for an Open
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.
• Turn the ignition OFF to the lock position.
• Disconnect the PCM C4 harness connector.
• Disconnect the transmission solenoid/pressure switch assembly harness connector.
• Measure the resistance of the L/R pressure signal circuit between the appropriate terminal of Miller tool #8815 and the transmission solenoid/pressure switch assembly harness connector.
Is the resistance more than 5.0 ohms?
Yes
• Repair the L/R pressure signal circuit for an open.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 7.
Test Step 7 - Check the L/R Pressure Signal Circuit for a Short to Ground
• Measure the resistance between ground and the L/R pressure signal circuit.
Is the resistance less than 5.0 ohms?
Yes
• Repair the L/R pressure signal circuit for a short to ground.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 8.
Test Step 8 - Check the L/R Pressure Signal Circuit for a Short to Voltage
• Ignition ON, engine not running.
• With the scan tool in the TIPM, actuate the TCM output.
• Measure the voltage of the L/R pressure signal circuit.
Is the voltage more than 0.5 volts?
Yes
• Repair the L/R pressure signal circuit for a short to voltage.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Using the schematics as a guide, check the powertrain control module terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for tune-ups or service bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. Refer to With the scan tool, perform Quick Learn.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
Test Step 9 - Intermittent Wiring and Connectors
• The conditions necessary to set this DTC are not present at this time.
• Test Drive the vehicle and verify if the transmission is launching in 2nd gear and/or there is no TCC engagement.
• With the scan tool, check the event data to help identify the conditions in which the DTC was set.
• Check for any service bulletins for possible causes that may apply.
Are there 2nd gear launches and/or no TCC engagement?
Yes
• Disassemble and inspect the valve body. Inspect the solenoid switch valve for sticking in its bore and repair or replace as necessary.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Test Complete.