P2703- INADEQUATE ELEMENT VOLUME UD

For a complete wiring diagram Refer to Section 8W.

Theory of Operation


The volumes of the transmission fluid needed to apply the friction elements are continuously monitored and learned for adaptive controls. As the clutch friction material wears, the volume of fluid needed to apply the clutch increases. Certain transmission mechanical problems can cause near-zero learned volumes resulting in setting a DTC. The DTC will usually set with other DTCs, which indicates an internal transmission problem.



Possible Causes
BROKEN UD ACCUMULATOR SPRING(S)
BROKEN UD CLUTCH PISTON SPRING OR DISLODGED SNAP RING
INTERNAL LEAKAGE IN PUMP OR VALVE BODY ASSEMBLIES
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE

Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)



Diagnostic Test

1. OTHER DTCS PRESENT

With the scan tool, check DTCs.

Are there any Pressure Switch Sense circuit DTCs present also?

Yes


No

2. CHECK UD CLUTCH VOLUME INDEX

With the scan tool, erase Transmission DTCs.

NOTE: The TRANS TEMP DEG must be at least 43 degrees C or 110 degrees F before performing the following steps.


Drive the vehicle and perform at least ten 4-3 kickdowns by depressing the throttle between 30 and 54 TPS degrees at speeds about 80 Km/h or 50 mph.
With the scan tool, read the UD clutch volume index (CVI).

Is the UD CVI below 10?

Yes


No

3. UD CLUTCH CIRCUIT LEAKS IN THE VALVE BODY

Turn the ignition off to the lock position.
Remove the transmission oil pan and valve body per the Service Information.
Check the condition of the UD accumulator springs.
Look for possible leak paths into the UD clutch hydraulics circuit within the valve body.

Were there any problems found?

Yes


No

4. AIR CHECK UD CLUTCH CIRCUIT

Perform an air check on the UD Clutch circuit per the Service Information.
Watch and listen for UD Clutch piston movement.
Air check all other pump passages for air leakage into the UD Clutch circuit.

Were any problems found?

Yes


No

5. VERIFY PCM OPERATION

NOTE: The TRANS TEMP DEG must be at least 43 degrees C or 110 degrees F before performing the following steps.


Perform eight learnable starts. A learnable start is defined as follows: Start engine. From a standstill, accelerate lightly to 80 Km/h or 50 mph, then brake lightly to a stop. Turn off engine.
With the scan tool, record the clutch volume index (CVI) for all clutches.
With the scan tool, perform a BATTERY DISCONNECT.
With the scan tool, read the CVIs and compare them to the readings recorded before the BATTERY DISCONNECT.

Are any of the CVIs less than 5 or different than before the BATTERY DISCONNECT?

Yes


No