Dodge Dakota (ND). Manual - part 954

P0944-LOSS OF HYDRAULIC PUMP PRIME

For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - SCHE-
MATICS AND DIAGRAMS)

For a complete wiring diagramRefer to Section 8W.

•

When Monitored:
Every 350 msec

•

Set Condition:
If the transmission begins to slip in any forward gear, and the pressure switch or switches that should be
closed for a given gear are open, a loss of prime test begins. All available elements (in 1st gear LR, 2/4 and
OD, in 2nd, 3rd, and 4th gear 2/4 and OD) are turned on by the PCM to see if pump prime exists. The code
is set if none of the pressure switches respond. The PCM will continue to run the loss of prime test until pump
pressure returns. The vehicle will not move or the transmission will slip. Normal operation will continue if pump
prime returns.

Possible Causes

LOW TRANSMISSION FLUID LEVEL

SHIFT LEVER POSITION

PLUGGED TRANSMISSION FILTER

TRANSMISSION OIL PUMP

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RLE - DIAGNOSIS AND TESTING).

Theory of Operation

The Loss of Prime Test is used to prevent transmission defaults and erroneous fault codes during temporary loss of
pump prime that may occur with low transmission fluid under severe braking conditions, start-up, etc. and to point
towards more subtle problems such as a plugged or ruptured oil filter. The Loss of Prime fault is set by a loss of
hydraulic pressure in the transmission system. This condition, if sustained, will result in the vehicle being unable to
move.

Diagnostic Test

CHECK TO SEE IF DTC P0944 IS CURRENT

Place the gear selector in park.

Start the engine.

NOTE: The Transmission Temperature must be at least 43° C (110° F) before performing the following steps.
The Transmission must be at operating temperature prior to checking pressure. Cold transmission fluid will result in
higher pressure readings.

Place the Transmission in Reverse.

With the scan tool, observe the Transmission Pressure Switch states.

Are any of the Pressure Switches closed?

Yes

>> Go To 2

>> Go To 4

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AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

P0944-LOSS OF HYDRAULIC PUMP PRIME (CONTINUED)

INTERMITTENT OPERATION

The conditions necessary to set this DTC are not present at this time.

Test drive the vehicle. Allow the Transmission to shift through all gears and ranges.

Was a delayed engagement and/or a no drive condition present during the test drive?

Yes

>> Go To 4

>> 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 wiring while checking for shorted and open circuits.

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

Were there any problems found?

Yes

>> Repair as necessary.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Test Complete.

SHIFT LEVER POSITION TEST

With the scan tool, perform a Shift Lever Position test. Follow the instructions on the screen.

Did the Shift Lever Position Test pass?

Yes

>> Go To 5

>> Perform the diagnostic procedure for P0706–CHECK SHIFTER SIGNAL.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

CHECK FOR PLUGGED TRANSMISSION FILTER

Remove the Transmission Pan and inspect the Transmission Fluid and Transmission Filter per the Service Informa-
tion.

Does the Transmission Oil Pan contain excessive debris and/or is the Oil Filter plugged?

Yes

>> Repair the cause of the plugged Transmission Filter. Refer to the Service Information for the proper

repair procedure.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Go To 6

TRANSMISSION OIL PUMP

If there are no possible causes remaining, view repair.

Repair

Replace the Transmission Oil Pump per the Service Information.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

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P0992-2/4/OD HYDRAULIC PRESSURE TEST

For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - SCHE-
MATICS AND DIAGRAMS)

For a complete wiring diagram Refer to Section 8W.

•

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 greater than 1000 RPM, the PCM momentarily turns on
element pressure to the clutch circuits that do not have pressure to identify that the correct pressure switch
closes. If the pressure switch does not close 2 times the DTC sets.

Possible Causes

CONDITION P0992 PRESENT

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RLE - DIAGNOSIS AND TESTING).

Theory of Operation

Pressure switches are normally off or open (no pressure applied) and read high (+12 volts). When an element is
applied, the corresponding pressure switch closes to ground (0 volts) or turns on. The controller tests the OD and
2/4 pressure switches when they are off (when the corresponding friction element is not applied) by briefly applying
the OD and 2/4 elements which will cause the corresponding pressure switch to close. The test verifies that the
switches are operational and that the switch will close when the corresponding element is applied. If a switch fails
to respond, it is re-tested. The MIL illuminates and the transmission system defaults to Limp-in mode.

CHECK TO SEE IF DTC P0992 IS CURRENT

NOTE: The vehicle must be driven to set this DTC. The transmission must at operating temperature with the
Engine RPM above 1000 RPM.
This DTC is an indication of both the 2/4 and the O/D Hydraulic Pressure Switch DTCs present.

Perform the diagnostic procedures for both P0845 and P0870.

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

If there are no possible causes remaining, view repair.

Repair

Refer to the Transmission category and perform the diagnostic procedures for P0845 and P0870.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

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AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

P1684-BATTERY WAS DISCONNECTED

For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - SCHE-
MATICS AND DIAGRAMS)

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
After a reset (ignition key turned to the RUN position).

•

Set Condition:
The checksum of the battery backed RAM does not match the stored checksum. Set Time: Less than 7 msec.

Possible Causes

BATTERY WAS DISCONNECTED

PCM WAS REPLACED OR DISCONNECTED

QUICK LEARN WAS PERFORMED

(A919) FUSED B+ CIRCUIT TO PCM OPEN

(Z908 and Z977) GROUND CIRCUIT OPEN

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RLE - DIAGNOSIS AND TESTING).

Theory of Operation

Note: This is not a fault code. It exists to provide reference information only. A battery backed RAM is used to
maintain some learned values. When the battery is disconnected, this memory is lost. When the battery is recon-
nected, the loss of learned values will be detected by the controller. The code will be set and the learned values will
be initialized to known constants and the learning process will continue. Setting the code has no effect except for
re-initialization of learned values.

Diagnostic Test

BATTERY WAS DISCONNECTED

Has the battery been disconnected, lost it’s charge, or been replaced recently?

Yes

>> Disconnecting or replacing the battery will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Go To 2

WAS QUICK LEARN PERFORMED

Has a Quick Learn procedure been performed?

Yes

>> Performing Quick Learn will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Go To 3

PCM REPLACED OR DISCONNECTED

Has the PCM been replaced or disconnected?

Yes

>> Replacing or disconnecting the PCM will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Go To 4

AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

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