Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0748

Line Pressure Control Solenoid Valve System Performance

DTC P0961

Line Pressure Control Solenoid Valve System Performance

DTC P0962

Line Pressure Control Solenoid Valve Control Circuit Low Voltage

DTC P0963

Line Pressure Control Solenoid Valve Control Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Signal	P0962	P0748, P0963	P0748, P0963	P0961
Low Reference	-	P0748, P0961, P0963	P0748, P0961, P0963	P0748, P0961, P0963

Typical Scan Tool Data

Line Pressure Control Solenoid Valve

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: 0.1-1.1 A
Signal	0 A	2.55 A	2.55 A
Low Reference	-	2.55 A	1
1. Internal TCM damage may occur if shorted to B+

Circuit/System Description

Line pressure control solenoid (SLT) is part of the front valve body. SLT regulates the transmission fluid line pressure in accordance with the value decided in the transmission control module (TCM) based on throttle opening signal and engine torque. Through this, it controls operating hydraulic pressure to the clutch and brakes for smooth shifting. The TCM varies the current to the normally SLT from 0.1 A for maximum line pressure, to 1.1 A for minimum line pressure. As a fail-safe function, if SLT abnormality occurs, the TCM will disable the current. In that case the line pressure is maximized.

Conditions for Running the DTC

P0748

•	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 P0962 and P0963 are not set.

P0961

•	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)

•	SLT current is more than 0.85 A.

•	SLT current is not changed.

P0962

•	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 P0963 is not set.

P0963

•	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 P0962 is not set.

Conditions for Setting the DTC

P0748

Deviation between commanded current and feedback current.

P0961

The TCM detects the error current more than 80 mA for 2.75 ms.

P0962

The TCM detects at least 5 times less than 23 mA current consumption of the SLT control circuit for 100 ms.

P0963

The TCM detects at least 5 times more than 1.333 A current consumption of the SLT control circuit for 100 ms.

Action Taken When the DTC Sets

P0748, P0961

•	DTC P0961 is a Type B DTC.

•	The TCM turns OFF all solenoids.

•	The TCM allows the vehicle after a stop to operate only in the second gear and “R” range.

P0962, P0963

•	DTCs P0962 and P0963 are Type B DTCs.

•	No self learning function.

•	The TCM turns OFF all solenoids.

•	The TCM allows the vehicle after a stop to operate only in the second gear and “R” range.

Conditions for Clearing the DTC

P0748, P0961

•	DTC P0963 is a Type B DTC.

•	The TCM detects the error current less than 50 mA for 2.75 ms.

P0962, P0963

•	DTCs P0962 and P0963 are Type B DTCs.

•	The current consumption of the SLT 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 under the optimal conditions to test solenoid electrical DTCs.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Description and Operation

Transmission Component and System Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

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's Line Pressure Control Solenoid Current parameter. The reading should be between 0.1 and 1.1 A.

4.	If the parameter in not within specified range or if the DTC resets, go to Circuit/System Testing.

Circuit/System Testing

Command the Line Pressure Control Solenoid Valve with a scan tool. The value should change from 0.0-1.1 A.

Component Testing

Static Test

1.	Ignition OFF, remove the K71 Transmission Control Module.

2.	Test for 5-5.6 Ω at 20°C (68°F) between the low reference circuit terminal 1 X2 and the voltage supply circuit terminal 3 X2.

3.	If less than the specified range, test the wiring harness for internal short. If the circuit test normal, replace the Q23 Line Pressure Control Solenoid Valve.

4.	Test for infinite resistance between each terminal and the low reference circuit terminal 1 X2 and also to the voltage supply circuit terminal 3 X2.

5.	If less than the specified range, replace the wiring harness.

6.	If all circuit test normal, perform the Control Solenoid Valve Inspection (M36 and MXE).

7.	If the inspection test normal, replace the valve body assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Control valve body replacement-Refer to Control Valve Body Replacement for replacement, setup, and programming.

•	TCM-Refer to Control Module References for replacement, setup and programming.

•	Perform the Transmission Adaptive Functions.

•	Wiring harness-Refer to Automatic Transmission Wiring Harness Replacement for replacement.