DTC 73 Pressure Control Solenoid Valve Electrical L57 MFI
Circuit Description
The pressure control (PC) solenoid valve is a transmission control module (TCM) controlled device that regulates the transmission line pressure. The TCM compares the throttle position (TP) sensor voltage, engine RPM, and other inputs in order to determine the appropriate line pressure for a given load. The TCM regulates the pressure by applying a varying amperage to the PC solenoid valve. The applied amperage can vary from 0.1 amps for maximum line pressure to 1.1 amps for minimum line pressure. The TCM monitors the circuit amperage.
If the TCM detects a PC duty cycle that exceeds 95% or is less than 1.9%, then DTC 73 sets.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | No system voltage DTC 75. |
Conditions for Setting the DTC
| • | The PC duty cycle exceeds 95% or is less than 1.9%. |
| • | All conditions met for 200 milliseconds (0.2 seconds). |
Action Taken When the DTC Sets
| • | The TCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The TCM disables the PC solenoid valve, defaulting the transmission to maximum line pressure. |
| • | The TCM stores DTC 73 in TCM history. |
Conditions for Clearing the DTC
| • | A scan tool clears the DTC from TCM history. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 consecutive key cycles without a diagnostic fault occurring. |
| • | The TCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the TCM. |
Diagnostic Aids
| • | Inspect the wiring at the TCM, the transmission connector and all other circuit connecting points for the following conditions: |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Reduced terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| - | Moisture intrusion |
| - | Corrosion |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | Inspect for any transmission DTCs that may have reset. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests the ability of the TCM to command the PC solenoid valve.
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This step tests the PC solenoid valve, and the automatic transmission (A/T) wiring harness assembly for incorrect resistance.
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This step tests the PC solenoid valve and the A/T wiring harness assembly for a short to ground.
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While performing this step, refer to Product Service Bulletin #9474L80E-07 for PC Solenoid Valve Application.
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This step tests the entire PC solenoid valve circuit for proper resistance.
-
This step tests for a short to ground in circuits 1228 and 1229 of the engine harness.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Important:: Before clearing the DTCs, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the TCM. Is the PC Act. Current reading always within the specified value of the PC Ref. Current? | 0.16 amps | Go to Diagnostic Aids | ||
Is the resistance within the specified value? | 3-7ohms | |||
4 |
Is the resistance within the specified range? | 3-7ohms | ||
5 | Replace the A/T wiring harness assembly. Refer to A/T Wiring Harness Replacement. Is the replacement complete? | -- | -- | |
Measure the resistance from terminal C in the J 39775 jumper harness to the transmission case. Is the resistance less than the specified value? | 9ohms | |||
7 | Inspect the A/T wiring harness assembly circuits 1228 (RED/BLK) and 1229 (LT BLU/WHT), for a short to ground condition. Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found? | -- | ||
|
Important:: Refer to Test Description 8 for information on component replacement. Replace the PC solenoid valve. Refer to Pressure Regulator Replacement . Is the replacement complete? | -- | -- | ||
Is the resistance within the specified range? | 3-7ohms | |||
Measure the resistance between harness terminal C1-D16 and a good ground. Is the resistance greater than the specified value? | 7ohms | |||
11 | Is the resistance in Step 9 greater than the specified value? | 7ohms | ||
12 | Inspect circuit 1228 (RED/BLK) and circuit 1229 (LT BLU/WHT) for an open. Refer to General Electrical Diagnosis in Wiring Systems. Was an open condition found? | -- | -- | |
13 | Inspect circuit 1228 (RED/BLK) and circuit 1229 (LT BLU/WHT) for a shorted condition. Refer to General Electrical Diagnosis in Wiring Systems. Was a shorted condition found? | -- | -- | |
14 | Inspect circuit 1228 (RED/BLK) and circuit 1229 (LT BLU/WHT) for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was a short to ground condition found? | -- | -- | |
15 | Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
16 | Replace the automatic transmission wiring harness assembly. Is the replacement complete? | -- | -- | |
17 | Replace the TCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |
18 | Perform the following procedure in order to verify the repair:
Is the PC Sol. Duty Cycle within the specified range? | 2-95% | System OK |
