P0750-LR SOLENOID CIRCUIT (CONTINUED)
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:
Initially at power-up, then every 10 seconds thereafter. The solenoid circuits will also be tested immediately
after a gear ratio or pressure switch error is detected.
•
Set Condition:
After three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio
or pressure switch error. Note: This DTC is strictly an electrical fault and does not apply to any internal
transmission failures.
Possible Causes
RELATED RELAY DTC’S PRESENT
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
(T20) LR SOLENOID CONTROL CIRCUIT OPEN
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO GROUND
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 Control System uses six electronically controlled solenoids that allow hydraulic fluid to be applied
to various friction elements (clutches), which enables the gear requested. The continuity of each solenoid circuit is
periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is
turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which
can be sensed by the Transmission Control System. If an inductive spike is not sensed by the Transmission Control
System during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate Diag-
nostic Trouble Code (DTC) is set. If the solenoid test is run in response to a gear ratio or pressure switch error, one
failure will result in setting the appropriate DTC. Note: This DTC is strictly an electrical fault and does not apply
to any internal transmission failures.
Diagnostic Test
1.
RELATED TRANSMISSION RELAY DTC’S PRESENT
With the scan tool, check for other transmission DTC’s.
Are there any Transmission Control Relay 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
HB
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS
21 - 429