P2725
DTC P2725 or P2728-P2730
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2725
- Brake Band Pressure Control Solenoid Valve Control Circuit Shorted
DTC P2728
- Brake Band Pressure Control Solenoid Valve Performance
DTC P2729
- Brake Band Pressure Control Solenoid Valve Control Circuit Low Voltage
DTC P2730
- Brake Band Pressure Control Solenoid Valve Control Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The shift control solenoid (SLB1) is installed on the front valve body. The solenoid linearly controls hydraulic pressure in response to signals output from the transmission control module TCM. Through this, the SLB1 controls operating hydraulic pressure to the brake for smooth shifting. According to each shift control solenoid assembly, the transmission shifts from 1st gear into 6th gear and vice versa. As a fail-safe function, if any shift control solenoid assembly abnormality occurs, the TCM will disable the current to the solenoids.
Conditions for Running the DTC
P2725
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* Driving in D range.
* TCM communication is normal.
* DTCs P2729 and P2730 are not set.
P2728
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* Driving in D range.
* TCM communication is normal.
* The automatic transmission fluid temperature is more than 20°C (68°F).
* SLB1 current is more than 0.85 A.
* SLB1 current is not changed.
P2729
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* Driving in D range.
* TCM communication is normal.
* DTC P2730 is not set.
P2730
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* Driving in D range.
* TCM communication is normal.
* DTC P2729 is not set.
Conditions for Setting the DTC
P2725
Deviation between commanded current and feedback current.
P2728
The TCM detects the error current more than 80 mA for 2.75 ms.
P2729
The TCM detects at least 5 times less than 23 mA current consumption of the SLB1 control circuit for 100 ms.
P2730
The TCM detects at least 5 times more than 1.333 A current consumption of the SLB1 control circuit for 100 ms.
Action Taken When the DTC Sets
P2725, P2728
* DTC P2725 and P2728 are Type B DTC.
* The TCM turns OFF all solenoids.
* The TCM allows the vehicle to operate only in the second gear and "R" range after a stop.
P2729, P2730
* DTCs P2729 and P2730 are Type B DTCs.
* No self learning function.
* The TCM turns OFF all solenoids.
* The TCM allows the vehicle to operate only in the second gear and "R" range after a stop.
Conditions for Clearing the DTC
P2725, P2728
* DTC P2725 and P2728 are Type B DTC.
* The TCM detects the error current less than 50 mA for 2.75 ms.
P2729, P2730
* DTCs P2729 and P2730 are Type B DTCs.
* The current consumption of the SLB1 control circuit is 0.1-1.1 A for 500 ms.
Diagnostic Aids
When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in 2nd gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM in the optimal condition to test solenoid electrical DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Description and Operation
Transmission Component and System Description (Transmission Component and System Description)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)
Circuit/System Verification
1. Ensure the transmission fluid temperature is between 50-80°C (122-176°F).
2. Operate the vehicle in 2nd gear long enough to ensure at least a 3°C (5°F) rise in transmission fluid temperature, then operate the vehicle in Park for 5 s.
3. Observe the scan tool Brake Band Pressure Control Solenoid Valve Current parameter. The reading should be between 0.1-1.1 A.
Circuit/System Testing
Command the Shift Brake Pressure Control Solenoid Valve with a scan tool. The value should change from 0.0-1.0 A.
If the value does not change, turn ignition OFF, remove the K71 Transmission Control Module. Connect a test lamp between the low reference circuit terminal 16 X2 at the K71 Transmission Control Module and the voltage supply component circuit terminal 21 X2 at the K71 Transmission Control Module. Command the Shift Brake Pressure Control Solenoid Valve with a scan tool. The test lamp has to illuminate brighter with increasing current.
If the test lamp always illuminates or always does not illuminate, replace the K71 Transmission Control Module.
Component Testing
Static Test
1. Ignition OFF, remove the K71 Transmission Control Module.
2. Test for 5-5.6 ohm at 20°C (68°F) between the low reference circuit terminal 16 X2 and the voltage supply circuit terminal 21 X2.
• If less than the specified range, test the wiring harness for internal short. If the circuit test normal, replace the Q27E Pressure Control Solenoid Valve 5.
3. Test for infinite resistance between each terminal and the low reference circuit terminal 16 X2 and also to the voltage supply circuit terminal 21 X2.
• If less than the specified range, replace the wiring harness.
4. If all circuit test normal, perform the Control Solenoid Valve Inspection (M36 and MXE) (AF40-6 - Automatic Transmission).
• If the inspection tests normal, replace the control valve body.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Control valve body replacement-Refer to Control Valve Body Replacement (Control Valve Body Replacement).
* TCM-Refer to Control Module References (Programming and Relearning).
* Wiring harness-Refer to Automatic Transmission Wiring Harness Replacement (Service and Repair).