DTC P0748, P0962, or P0963
Diagnostic Instructions
DTC Descriptors
| DTC P0748: 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
|
Line Pressure Control Solenoid Control
|
P0962
|
P0748, P0963
|
P0748, P0963
|
-
|
Low Reference
|
-
|
P0748, P0963
|
P0748, P0963
|
P0748, 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: 100-1 100 mA
|
Line Pressure Control Solenoid Control
|
0 mA
|
0 mA
|
2 550 mA
|
Low Reference
|
-
|
0 mA
|
1
|
1. Internal transmission control module (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. |
| • |
TCM communication is
normal. |
| • |
DTCs P0962 and P0963 are not
set. |
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. |
| • |
TCM communication is
normal. |
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. |
| • |
TCM communication is
normal. |
Conditions for Setting the DTC
P0748
Deviation between commanded current and feedback current.
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
| • |
DTC P0748 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
| • |
DTC P0748 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
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 Line
Pressure Control Solenoid Valve Current parameter, the reading
should be between 0.1-1.1 A. |
| ⇒ |
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.
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 1 X2 at the K71 Transmission Control
Module and the voltage supply component circuit terminal 3 X2 at
the K71 Transmission Control Module. Command the Line Pressure
Control Solenoid Valve with a scan tool. The test lamp has to
illuminate brighter with increasing current. If the test lamp
always illuminate 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 Ω at
20°C (68°F) between the low reference circuit terminal 1 X2
and the voltage supply circuit terminal 3 X2. |
| ⇒ |
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. |
| 3. |
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. |
| ⇒ |
If less than the specified range, replace the
wiring harness. |
| ⇒ |
If the inspection test normal, replace the valve
body assembly. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
