11 .CHECK PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Line Pressure Adapter, Miller tool #8259 and 0-300 psi Test Gauge, Miller tool #C-3293-SP.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator, Miller tool #8333.
On the Transmission Simulator, turn the Pressure Switch selector switch to4C.
Ignition on, engine not running.
With the scan tool, monitor the 4C Pressure Switch state while pressing andholding the Pressure Switch test button
and wiggling the wire harness and connectors that pertain to the 4C PressureSwitch.
Did the 4C Pressure Switch state change to closed and remain closed while wiggling the wires?
Ye s>>
Go To 12
No>>
Go To 14
12.CHECK FOR EXCESSIVE DEBRIS
Turn the ignition off to the lock position.
Remove the Transmission Simulator, Miller tool #8333.
Remove and inspect the Transmission Oil Pan per the Service Information.
Does the Transmission Oil Pan contain excessive debris or contamination?
Ye s>>
Repair the cause of the excessive debris in the Transmission Oil Pan. Referto the Service Information
for the proper procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 13
13.CHECK 4C HYDRAULIC CLUTCH CIRCUIT
Remove the Valve Body and air check the 4C hydraulic clutch circuit (in the case) for leakage per the Service
Information.
NOTE: The 4C hydraulic clutch circuit contains a small bleed orifice. A small amount of air leakage is nor-
mal.
Was there excessive air leakage noticed during the air check?
Ye s>>
Repair as necessary. Check the 4C clutch piston, piston seals and bleed orifice assembly.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Disassemble and inspect the Valve Body and repair as necessary. Inspect the 4C Accumulator piston
and seals. If no problems are found in the Valve Body, replace the Transmission Solenoid/TRS Assem-
bly per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
16.CHECK THE (T48) 4C PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Disconnect all PCM harness connectors.
Disconnect the Transmission Solenoid/TRS Assembly harness connec-
tor.
NOTE: Make sure the Transmission Solenoid/TRS Assembly har-
ness connector is disconnected.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the (T48) 4C Pressure Switch Sense
circuit and all other circuits in the Transmission Solenoid/TRS Assembly
harness connector.
Is the resistance below 5.0 ohms between the (T48) 4C Pres-
sure Switch Sense circuit and any other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T48) 4C Pressure Switch Sense circuit for a
short to another circuit(s).
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)terminals for corrosion,
damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems
are found, replace the PCM per the Service Information. With the scan tool,perform QUICK LEARN.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
17.CHECK WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
If the DTC EVENT DATA shows the DTC Pie set while the Line Pressure was significantly below the Desired Line
Pressure reading, check for causes of low line pressure (low fluid level, broken or mis-installed primary oil filter or
filter seal, sticking Main Regulator Valve in the Pump Valve Body etc.). IfthedatashowstheDTCsetwhiletheLine
Pressure reading was significantly higher than the Desired Line Pressure, check the Line Pressure Sensor and
related wiring.
Where there any problems found?
Ye s>>
Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
P0988-4C PRESSURE SWITCH RATIONALITY
For a complete wiring diagramRefer to Section 8W
When Monitored:
Continuously with the ignition on, engine running, with the transmissionin gear.
Set Condition:
The DTC is set if the 4C Pressure Switchreadsopenorclosedatthewrongtimein a given gear.
Possible Causes
RELATED TCM POWER INPUT DTCS PRESENT
DTC P0871 ALSO PRESENT
LOSS OF 12-VOLT FEED
(T48) 4C PRESSURE SWITCH SENSE CIRCUIT OPEN
(T48) 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
EXCESSIVE FLUID LEAKAGE WITH 2C CLUTCH CIRCUIT
#5 AND/OR #7 CHECK BALL CUT OR DAMAGED
LOW LINE PRESSURE
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE
WIRING AND CONNECTORS
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
The Transmission system uses five pressure switches to monitor the fluid pressure in the LR, 2C, 4C, UD, and OD
clutch circuits. The pressure switches are continuously monitored for the correct states in each gear as shown.
GEAR L/R 2C 4C UD OD
REVERSEOPEN OPEN OPEN OPEN OPEN
P/NCLOSED OPEN OPEN OPEN OPEN
1STCLOSED* OPEN OPEN CLOSED OPEN
2NDOPEN CLOSED OPEN CLOSED OPEN
2ND PRIMEOPEN OPEN CLOSED CLOSED OPEN
DRIVEOPEN OPEN OPEN CLOSED CLOSED
4THOPEN OPEN CLOSED OPEN CLOSED
5THOPEN CLOSED OPEN OPEN CLOSED
*L/R is closed if output speed is below 100 rpm in Drive and Manual 2. L/R is open in Manual 1.
Diagnostic Test
1.CHECK FOR TCM POWER INPUT SIGNAL DTCS
With the scan tool, check for other transmission DTCs.
Are there any TCM Power Input DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
7.CHECK IF THE DTC P0871 ALSO SET
With the scan tool, check Transmission DTCs.
Is the DTC P0871 also present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 8
8.CHECK IF THE DTC SET IN PARK, REVERSE OR NEUTRAL
With the scan tool, check the DTC EVENT DATA for P0988.
NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test
procedure.
Does the DTC EVENT DATA show the DTC set in Park, Neutral, or Reverse for P0988?
Ye s>>
Go To 13
No>>
Go To 9
9.CHECK IF THE DTC EVENT DATA READS CLOSED
With the scan tool, check the DTC EVENT DATA for P0988.
NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test
procedure.
Does the DTC EVENT DATA show the 4C Pressure Switch reading CLOSED?
Ye s>>
Go To 11
No>>
Go To 10
10.CHECK THE PRIMARY OIL FILTER SEAL
In the DTC EVENT DATA recorded earlier,compare the Line Pressure and the Desired Line Pressure.
Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?
Ye s>>
Repair as necessary to correct low line pressure. Check fluid level and adjustasnecessary.Iffluidlevel
is OK, check the Primary Oil Filter seal for a split, crack, or improperly installed. If the filter and seal are
OK, check the Main Regulator Valve in the Oil Pump. Refer to the Service Information for the above
procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 15
11 .CHECK THE PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector switchtothe4Cposition.
With the scan tool, monitor the 4C Pressure Switch while pressing the Pressure Switch test button on the Trans-
mission Simulator.
Did the state of the 4C Pressure Switch change while pressing the Pressure Switch Test button?
Ye s>>
Go To 12
No>>
Go To 13
12.CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
Where there any problems found?
Ye s>>
Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Replace the Transmission Solenoid/TRS Assembly per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
13.CHECK THE (T48) 4C PRESSURE SWITCH SENSE CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333.
Disconnect the PCM C4 harness connector.
Connect Miller tool #8815 to the PCM C4 harness connector.
CAUTION: 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 per-
form diagnosis.
Measure the resistance of the (T48) 4C Pressure Switch Sense circuit
between the Transmission Solenoid/TRS Assembly harness connector
and the appropriate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T48) 4C Pressure Switch Sense circuit for an
open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 14
P128B-TCM POWER CONTROL CIRCUIT 2 LOW - TIPM
For a complete wiring diagramRefer to Section 8W.
3.CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Connect the TIPM C10 harness connector.
Disconnect the Transmission Solenoid/Pressure Switch harness connec-
tor.
Disconnect the Line Pressure Sensor/Variable Force Solenoid harness
connector (if equipped).
Ignition on, engine not running.
Using the scan tool under the TIPM Actuators, actuate the Transmis-
sion.
Using a 12-volt test light connected to ground, check the (T16) Trans-
mission Control Output circuits.
NOTE: The test light must illuminate brightly. Compare the bright-
ness to that of a direct connection to the battery.
Does the test light illuminate brightly at all the (T16) Transmis-
sion Control Output circuits?
Ye s>>
Go To 4
No>>
Repair the (T16) Transmission Control Output circuit for an
open.
Perform 545RFE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
4.TOTALLY INTEGRATED POWER MODULE
Using the schematics as a guide, inspect the wire harness and connectors.
Check the TIPM harness connector terminals for corrosion, damage, or terminal push out.
Pay particular attention to all power and ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform 545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module per Service Information.
Perform 545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Were any problems found?
Ye s>>
Repair as necessary.
Perform 545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Te s t c o m p l e t e .