Jeep Grand Cherokee WK. Manual - part 1316

P0725-ENGINE SPEED SENSOR CIRCUIT

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

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
Continuously every 7 msec with the ignition on and engine running.

•

Set Condition:
This DTC will set when the calculated engine speed is less than 390 RPM with the engine running, or greater
than 8000 RPM, for the period of 2.0 seconds. The PCM will place the Transmission in Limp-in when this DTC
is set. Note: This is not a Transmission Input Speed Sensor DTC.

Possible Causes

RELATED ENGINE DTC’S PRESENT

CRANK POSITION SENSOR OR WIRING

POWERTRAIN CONTROL MODULE

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 Control System calculates the engine RPM by directly reading the engine crank position sensor.
It compares the calculated value to the engine speed sensor signal transmitted from the Engine Control System
over the controllers internal bus. The calculated engine RPM is also compared to a minimum and a maximum value.
Note: Due to the integration of the Powertrain Control Module (PCM) and Transmission Control Module
(TCM), bus communication between the modules is internal and unserviceable.

Diagnostic Test

RELATED ENGINE DTCS PRESENT

NOTE: This is not a Transmission Input Speed Sensor DTC.
Ignition on, engine not running.

With the scan tool, read all Engine DTC’s. This includes any active or stored or one trip DTCs.

Are there any engine RPM related DTCs present?

Yes

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

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

>> Go To 2

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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS

P0725-ENGINE SPEED SENSOR CIRCUIT (CONTINUED)

VERIFY IF THE DTC IS CURRENT

Ignition on, engine not running.

With a scan tool, read and record all EATX DTC EVENT DATA.

With the scan tool, erase all active and stored transmission DTCs. (Note: it may be necessary to perform a battery
disconnect with the scan tool to clear EATX DTC EVENT DATA.)

Using the EATX DTC EVENT DATA, duplicate the conditions in which the original DTC set.

With the scan tool, read transmission and engine DTCs.

NOTE: Refer to all engine DTCs first in the following question.

Pick the answer below that best describes your findings, (this includes one trip failures).

Transmission DTC P0725 set

Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion,
damage, or terminal push out. Also check the Crank Position sensor and wiring. 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.

Engine DTC set

Refer to the Driveability category and perform the appropriate symptom.

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

No DTC set at all

Go To 3

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.

Were there any problems found?

Yes

>> Repair as necessary.

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

>> Test Complete.

AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS

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P0731-GEAR RATIO ERROR IN 1ST

For the Transmission circuit diagram (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:
If the ratio of the Input RPM to the Output RPM does not match the current gear ratio. This DTC can take up
to five minutes of problem identification before illuminating the MIL

Possible Causes

CUT UD PISTON SEAL

LOW FLUID LEVEL

CRACKED OR MISINSTALLED PRIMARY OIL FILTER OR SEAL

STUCK OR STICKING MAIN REGULATOR VALVE

FAILED OVERRUNNING CLUTCH

CUT UD ACCUMULATOR SEAL RING

BROKEN UD ACCUMULATOR PISTON

BROKEN REACTION SHAFT SUPPORT SEAL RING

LOW LINE PRESSURE

BROKEN / MISSING MAIN VALVE BODY BLEED ORIFICE

BROKEN / MISSING DRIBBLER ORIFICE ASSEMBLY IN REACTION SHAFT SUPPORT

POOR MACHINING ON PUMP VALVE BODY FACE

INPUT SPEED SENSOR AND RELATED WIRING

TRANSMISSION SOLENOID/TRS ASSEMBLY

POWERTRAIN CONTROL MODULE

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 two speed sensors, one to measure input RPM and one to measure output RPM.
These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through
the following checks:

1) Once in a particular gear, if the gear ratio varies from the correct gear ratio, the corresponding in-gear trouble
code is set (DTCs P0731–36).

2) An excessive change in input or output speeds indicating signal intermittent may result in the DTCs P0715 and/or
P0720 being set.

3) If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed
sensor when at a stop in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the
output speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause
the DTC P1794 to set.

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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS

P0731-GEAR RATIO ERROR IN 1ST (CONTINUED)

Diagnostic Test

DETERMINING IF RELATED DTC’S ARE PRESENT

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

If any of these DTC’s are present, perform their respective tests first.

Are there any Transmission; solenoid, line pressure, speed sensor, and/or loss of prime DTC’s present?

Yes

>> Refer to the Transmission category and perform the appropriate symptom. If any of these DTCs are

present, they may cause a Speed Ratio Error. Perform the test for P0944 first if it is present.

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

>> Go To 2

CHECK TO SEE IF DTC P0731 IS CURRENT

With the scan tool, perform the 1st Gear Clutch Test. Follow the instructions on the scan tool.

Increase the throttle angle or TPS Degree to 30° for no more than a few seconds.

CAUTION: Do not overheat the transmission.

Did the Clutch Test pass, Input Speed remain at zero?

Yes

>> Go To 3

>> Go To 4

CHECK FOR INTERMITTENT OPERATION

The conditions to set this DTC are not currently present.

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

- If the DTC Event Data shows fault P0731 was set in Park, Reverse, or Neutral, replace the Powertrain Control
Module.

- If the DTC Event Data shows fault P0731 set with input RPM = zero, check the input speed sensor and related
wiring.

- If the DTC Event Data shows fault P0731 set with line pressure significantly below desired line pressure, check for
the cause of low line pressure (i.e., oil level, misinstalled or damaged primary filter or filter seal, sticking main reg-
ulator valve in pump, etc.).

- If the DTC Event Data shows fault P0731 set with the UD pressure switch open (but line pressure matches
Desired Line Pressure), air check the UD hydraulic clutch circuit for leakage per the Service Information. If the UD
hydraulic clutch circuit is OK, replace the solenoid/TRS assembly.

Check the gearshift linkage adjustment.

Intermittent Gear Ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed
Sensor Ground circuit.

Remove the Starter Relay.

NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.
Install Transmission Simulator, Miller tool #8333.

Wiggle wiring and connectors while checking for intermittent operation with the Transmission Simulator.

Gear ratio DTC’s can also be set under extreme temperature conditions.

Verify if the problem is only experienced under extreme hot or cold conditions.

Were there any problems found.

Yes

>> Repair as necessary.

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

>> Test Complete.

AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS

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