DTC Troubleshooting: P177A
DTC P177A: Line Pressure Solenoid Valve A Or Line Pressure Switch Stuck OFF
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review the General Troubleshooting Information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P177A Line Pressure Solenoid Valve A Or Line Pressure Switch Stuck OFF
      

1.
ATF check:

ATF check
?1.
Warm up the engine to normal operating temperature (the radiator fan comes on).

?2.
Make sure that the transmission is filled to the proper level, and check for fluid leaks.

?3.
Drain the ATF through a strainer. Inspect the strainer for metal debris or excessive clutch material.

Does the strainer have metal debris or excessive clutch material?

     
YES
     
     
     
     
NO
     
     
     
Replace the ATF, then go to step 2.
2.
Problem verification:

Problem verification
?1.
Raise the vehicle on a lift, or apply the parking brake, block the rear wheels, and raise the front of the vehicle. Make sure it is securely supported, and allow the front wheels to rotate freely.

?2.
Press the engine start/stop button to select the ON mode.

?3.
Clear the DTC with the HDS.


?4.
Start the engine.

?5.
Monitoring the APP Sensor (%) with the HDS, press (2 % opened) and release (0 % opened) the accelerator pedal every 2 seconds. Then check the Line Pressure Sol VLV. A signal and the Line Pressure Pressure Switch signal with the HDS.
Signal
Current conditions
Values
Unit
APP Sensor (%)
    
Line Pressure Sol VLV. A
    
Line Pressure Pressure Switch
    

Is the Line Pressure Pressure Switch ON when Line Pressure Sol VLV. A is ON, and OFF when Line Pressure Sol VLV. A is OFF?

     
YES
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals between the line pressure switch and the PCM.?
     
NO
     
     
     
The failure is duplicated. Go to step 3.
3.
Determine possible failure area (IG1(VBSOL) line, others):

Determine possible failure area (IG1(VBSOL) line, others)
?1.
Select the Line Pressure Solenoid Test in the Miscellaneous Test Menu, and check that line pressure solenoid valve A operates with the HDS.

  

Is a clicking sound heard?

     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
Go to step 4.
4.
Fuse check:

Fuse check
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Check the following fuse.
Fuse
No. B13 (15 A)
Location
Under-dash fuse/relay box

Is the fuse OK?

     
YES
     
     
     
The fuse is OK. Go to step 5.
     
NO
     
     
     
Replace the No. B13 (15 A) fuse, and recheck. If the fuse blows again, repair a short to body ground on the No. B13 (15 A) fuse circuit, and recheck.?
5.
Open wire check (IG1(VBSOL) line):

Open wire check (IG1(VBSOL) line)
?1.
Jump the SCS line with the HDS.


?2.
Disconnect the following connector.

?3.
Press the engine start/stop button to select the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
 
PCM connector B (51P): disconnected
Test circuit
IG1(VBSOL)
Test point 1
PCM connector B (51P) No. 1 (TAN)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG1(VBSOL) wire is OK. Faulty line pressure solenoid valve A. Replace the secondary valve body (line pressure solenoid valve A).?
     
NO
     
     
     
Repair an open in the IG1(VBSOL) wire between the PCM and the No. B13 (15 A) fuse in the under-dash fuse/relay box.?
6.
Line pressure switch check:

Line pressure switch check
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Line pressure switch 1P connector No. 1 (BRN)
Terminal B
Body ground


?4.
Press the engine start/stop button to select the ON mode.

?5.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
Line Pressure Pressure Switch
ON
      

Do the current condition(s) match the threshold?

     
YES
     
     
     
     
NO
     
     
     
The line pressure switch is OK. Go to step 7.
7.
Open wire check (OPPLSW line):

Open wire check (OPPLSW line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Remove the jumper wire.

?3.
Jump the SCS line with the HDS.


?4.
Disconnect the following connector.

?5.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
Line pressure switch 1P connector: disconnected
 
PCM connector B (51P): disconnected
Test circuit
OPPLSW
Test point 1
Line pressure switch 1P connector No. 1 (BRN)
Test point 2
PCM connector B (51P) No. 37 (BRN)


Is there continuity?

     
YES
     
     
     
The OPPLSW wire is OK. Replace the PCM.?
     
NO
     
     
     
Repair an open in the OPPLSW wire between the line pressure switch and the PCM.?