Dodge Ram Truck 1500-2500-3500. Manual — part 1643

P0987-4C HYDRAULIC PRESSURE TEST (CONTINUED)

16.

(T48) 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHER CIRCUITS

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 Assem-
bly 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?

Yes

>> Repair the (T48) 4C Pressure Switch Sense circuit for a

short to other circuit(s).

Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1.

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.

17.

INTERMITTENT 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 specific to this circuit.

Wiggle the wires while checking for shorted and open circuits.

With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.

If the EATX DTC EVENT DATA shows the DTC P0987 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.). If the data shows the DTC set
while the Line Pressure reading was significantly higher than the Desired Line Pressure, check the Line Pressure
Sensor and related wiring.

Where there any problems found?

Yes

>> Repair as necessary.

Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.

No

>> Test Complete.

21 - 504

AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS

DR/DH

P0988-4C PRESSURE SWITCH RATIONALITY

DR/DH

AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS

21 - 505

P0988-4C PRESSURE SWITCH RATIONALITY (CONTINUED)

For the Transmission circuit diagram (Refer to )(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/
545RFE - SCHEMATICS AND DIAGRAMS).

For a complete wiring diagram Refer to Section 8W

•

When Monitored:
Continuously with the ignition on, engine running, with the transmission in gear.

•

Set Condition:
The DTC is set if the 4C Pressure Switch reads open or closed at the wrong time in a given gear.

Possible Causes

RELATED RELAY DTC’S 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 Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING).

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

REVERSE

OPEN

OPEN

OPEN

OPEN

OPEN

P/N

CLOSED

OPEN

OPEN

OPEN

OPEN

1ST

CLOSED*

OPEN

OPEN

CLOSED

OPEN

2ND

OPEN

CLOSED

OPEN

CLOSED

OPEN

2ND PRIME

OPEN

OPEN

CLOSED

CLOSED

OPEN

DRIVE

OPEN

OPEN

OPEN

CLOSED

CLOSED

4TH

OPEN

OPEN

CLOSED

OPEN

CLOSED

5TH

OPEN

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.

21 - 506

AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS

DR/DH

P0988-4C PRESSURE SWITCH RATIONALITY (CONTINUED)

Diagnostic Test

1.

DETERMINING IF RELATED RELAY DTC’S ARE PRESENT

With the scan tool, check for other transmission DTC’s.

Are there any Transmission Control Relay related DTC’s present?

Yes

>> Refer to the Transmission category and perform the appropriate symptom.

Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.

No

>> Go To 2

2.

EATX DTC DATA SHOW CURRENT DTC

With the scan tool, check the EATX DTC EVENT DATA.

Does the EATX DTC EVENT DATA show data for DTC P0988?

Yes

>> Go To 3

No

>> Refer to the Transmission category and perform the appropriate symptom shown in the EATX DTC

EVENT DATA.

Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.

3.

MULTIPLE DTCS PRESENT

With the scan tool, check for other transmission DTC’s.

Are there two or more related Pressure Switch Sense DTCs present in addition to P0988?

Yes

>> Go To 4

No

>> Go To 7

4.

RELATED DTC PRESENT

With the scan tool, check the EATX DTC EVENT DATA for P0988.

NOTE: Make sure to record all EATX DTC EVENT DATA stored in the scan tool for future reference in this
test procedure.

Do all the pressure switches read CLOSED in the EATX DTC EVENT DATA for P0988?

Yes

>> Refer to Transmission category and perform diagnostics for the DTC P0888.

Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.

No

>> Go To 5

5.

EATX DTC EVENT DATA READ OPEN

In the EATX DTC EVENT DATA recorded earlier, read the state of all pressure switches.

Do all the pressure switches read OPEN?

Yes

>> Go To 6

No

>> Go To 7

DR/DH

AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS

21 - 507