Line Pressure Test
CAUTION:
Parking and service brakes must be applied throughout line pressure test. Total time for testing with vehicle in any driving gear should not exceed 2 minutes. Transaxle damage may occur.
- Before performing line pressure test, check fluid level and condition. Check manual control linkages for correct adjustment, and ensure engine is properly tuned.
- Connect scan tool to vehicle. Start engine and check for Diagnostic Trouble Codes (DTCs). If DTCs are present, go to the AUTO TRANS DIAGNOSIS - 4T65-E
article. If DTCs are not present, turn engine off. Connect oil pressure gauge to line pressure test port. See Fig 1.
- Start engine and allow it to warm to normal operating temperature. Using scan tool, access Pressure Control Solenoid (PCS) control test (PC Sol.). Using scan tool, increase pressure control solenoid current in increments of .1 amp. Allow pressure to stabilize for 5 seconds after each pressure change.
- With engine at idle, read corresponding line pressure on oil pressure gauge. Compare PCS current reading on scan tool and line pressure reading on gauge. See PCS CURRENT VS. LINE PRESSURE SPECIFICATIONS AT IDLE table.
- Shift transaxle to specified shift position. Measure minimum line and full line pressure. See LINE PRESSURE SPECIFICATIONS table. Record line pressure readings in all gear selector positions and compare recorded pressures to specifications.
- If pressure readings are not as specified, refer to SYMPTOM DIAGNOSIS under TROUBLE SHOOTING for diagnosis.
PCS CURRENT VS. LINE PRESSURE SPECIFICATIONS AT IDLE
| PCS Current In Amps |
PSI |
| .02 |
170-190 |
| .10 |
165-185 |
| .20 |
160-180 |
| .30 |
155-175 |
| .40 |
148-168 |
| .50 |
140-160 |
| .60 |
130-145 |
| .70 |
110-130 |
| .80 |
90-115 |
| .90 |
65-90 |
| .98 |
55-65 |
LINE PRESSURE SPECIFICATIONS
| Pressure Range & Shift Position |
PSI: (kPa) |
| Minimum Line |
| "D4", "D3" & "D2" |
74-86 (512-592) |
| "D1" |
146-187 (1005-1289) |
| "P", "R" & "N" |
79-101 (542-696) |
| Full Line |
| "D4", "D3" & "D2" |
167-203 (1153-1400) |
| "D1" |
146-187 (1005-1289) |
| "P", "R" & "N" |
223-271 (1540-1869) |
Courtesy of GENERAL MOTORS CORP.