5R55N Line Pressure Test

The line pressure tap is used to verify output pressure from Pressure Control (PCA(pos.3) or PCB(pos.10)) by turning either one off while verifying the output from the solenoid. The second pressure tap is used to verify the output from PCC solenoid.

This test verifies that the line pressure is within specifications.


1. Connection point (PCA or PCB).
2. Start engine and check line pressures, see below.
3. If pressures are not of range, check pressure on PCC port.

S-Type 3.0 Ltr, 4.0 Ltr:
Level in P/N: Idle -PC C=5, WOT Stall -PC C=5, Idle Line=125-165, WOT Stall Line=N/A

Level in R: Idle -PC C=116, WOT Stall -PC C=116, Idle Line=110-150, WOT Stall Line=290-360

Level in D/4: Idle -PC C=115, WOT Stall -PC C=115, Idle Line=110-150, WOT Stall Line=210-260

Level in 3: Idle -PC C=5, WOT Stall -PC C=5, Idle Line=N/A, WOT Stall Line=N/A

Level in 2: Idle -PC C=5, WOT Stall -PC C=5, Idle Line=N/A, WOT Stall Line=N/A

If the line pressure is not within the specifications, check PC C pressure.


Connect the pressure gauge as illustrated to PCC. Start engine, check pressures. See above specifications, and verify that the pressure is within its parameter.

Note, is the electrical, electronic side is without malaise, then pursue the list down below which designates itself to possible mechanical failures.

Test Results and Possible Causes

High at Idle- All Ranges:
Wiring Harnesses, EPC Boost Valve, EPC Solenoid, Main Regulator Valve

Low at Idle- All Ranges:
Low Fluid Level, Fluid Inlet Filter/Seal, Main Control Body, Cross Leaks, Gaskets, Pump, Separator Plate

Low - All Forward Ranges:
Forward Clutch, Main Control Body, Overdrive Servo, Intermediate Servo

Low in Park Only:
Valve Body

Low In Reverse Only:
Separator Plate, Rear Servo Piston, Cover Seal, reverse Clutch, Overdrive Servo, Intermediate Servo, Valve Body, Forward Clutch

Low in Neutral Only:
Valve Body, Overdrive Servo, Intermediate Servo

Low in D Only:
Forward Clutch, Overdrive Servo, Intermediate Servo, Valve Body

Low in 4 Only:
Forward Clutch, Overdrive Servo, Intermediate Servo, Valve Body

Low in 2nd Position Only:
Intermediate Servo, Overdrive Servo, Forward Clutch

Statistic: Known Issues
7x Main Control Valve Body (PC A,B,C (see Valve Body picture pos. 3,6,10,14)).
Wear (pressure loss) at 3 PC valves can be greater than at the servo bore holes when added together.
6x Intermediate Servo (1 bore)
6x overdrive Servo (1 bore)
5x Forward Clutch

General Service Information

General Service Information

Rear axle

Rear sub-frame

Front axle

Lower ball-point joint, Shock absorber bushes, Stabilizer bar links + mounts

Brake disc and pads


Intake Manifold / Ignition Coils / Spark-plugs/ engine-block ventilation (elbow)


Starter system

Valve clearance, timing-chain, tensioner and glides:
With valve clearance in its tolerance, there was no need to take the camshafts down, so tensioners and co. have to wait, the good thing is the tensioner pumps up in 3-4 min. the rattle noise disappears.

Cruise control malfunction, emergency mode

Automatic Transmission 5R55N

Info, tips, Fail Safe Mode

Stall Speed Test procedure and diagnoses

Valve Body, known issues

Valve Body, Solenoid test procedures

Line Pressure Test

Self made press for pressing down clutch drum springs, checking clutch tolerance without a dial gauge


Air Conditioning

Miscellaneous repairs

Wind-shield-wiper mechanism:
Time on the lot took its toll, wind-shield-wiper shafts had seized, uninstalled the mechanism, freed the seized shafts through the use of a good rust loosener, heat, force.

Water in Spark-plug wells 3-2 cylinder:
After days of heavy rain the engine began to misfire with accounted trouble codes, spark-plug wells were wet, an ionized rusty red path on the ceramic insulator had developed which shorted the HV ignition spark.

Connected the radio controls to the multi-functional steering wheel using an analog digital converter.