P1788

Test 1 Through 2:

Test 3 Through 7:

Test 8 Through 12:

SYMPTOM:
P1788-2/4 HYDRAULIC PRESSURE TEST FAILURE

When Monitored and Set Condition:
P1788-2/4 HYDRAULIC PRESSURE TEST FAILURE

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 > 1000 RPM, the TCM momentarily turns on element pressure to the clutch ckts that don't have pressure to identify the correct pressure sw closes. If the pressure sw does not close 2 times the code sets.

POSSIBLE CAUSES
INTERMITTENT WIRING & CONNECTORS
INTERNAL TRANSMISSION PROBLEM - 2-4 PRESSURE TEST
RELATED SPEED RATIO AND/OR PRESSURE SWITCH DTCS PRESENT
TRANSMISSION RELAY OUTPUT CIRCUIT OPEN
2-4 PRESSURE SWITCH SENSE CIRCUIT OPEN
2-4 PRESSURE SWITCH CIRCUIT SHORT TO GROUND
2-4 PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
REPLACE THE TCM
INCORRECT FLUID LEVEL