For 1990-2009 cars

### 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 Descriptor

DTC P0778: Pressure Control Solenoid Valve 1 System Performance - Feedback Current Stuck
DTC P0965: Pressure Control Solenoid Valve 1 System Performance - Terminal Short
DTC P0966: Pressure Control Solenoid Valve 1 Control Circuit Low Voltage
DTC P0967: Pressure Control Solenoid Valve 1 Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Signal | P0966 | P0778, P0967 | P0778, P0967 | P0965
Low Reference | -- | P0778, P0965, P0967 | P0778, P0965, P0967 | P0778, P0965, P0967

### Typical Scan Tool Data

#### Line PC Solenoid Valve

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: 0.1 A to 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

The shift control solenoid (SLC1) is installed on the front valve body. The solenoid linearly control hydraulic pressure in response to signals output from the transmission control module TCM. Through this, the SLC1 controls operating hydraulic pressure to the clutch 1 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

#### P0778

• | The ignition voltage is between 10.2 V and 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 P0966 and P0967 are not set.

#### P0965

• | The ignition voltage is between 10.2 V and 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)

• | SLC1 current is more than 0.85 A.

• | SLC1 target current is not changed.

#### P0966

• | The ignition voltage is between 10.2 V and 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 P0967 is not set.

#### P0967

• | The ignition voltage is between 10.2 V and 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 P0966 is not set.

### Conditions for Setting the DTC

#### P0778

Deviation between commanded current and feedback current.

#### P0965

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

#### P0966

The TCM detects at least 5 times less than 23 mA current consumption of the SLC1 control circuit for 100 ms.

#### P0967

The TCM detects at least 5 times more than 1.333 A current consumption of the SLC1 control circuit for 100 ms.

### Action Taken When the DTC Sets

#### P0778, P0965

• | DTC P0965 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.

#### P0966, P0967

• | DTCs P0966 and P0967 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

#### P0778, P0965

• | DTC P0967 is a Type B DTC.

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

#### P0966, P0967

• | DTCs P0966 and P0967 are Type B DTCs.

• | The current consumption of the SLC1 control circuit is between 0.1 A and 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 data Clutch Pressure Control Solenoid Valve 1 Current parameter, the reading should be between 0.1 A - 1.1 A.

### Circuit/System Testing

Command the Clutch PC Solenoid Valve 1 or Increase and Decrease with a scan tool. The value should rise from 0.1 A to 1.1 A and return to 0.1 A.

⇒ | If the value does not change, turn ignition OFF, remove the K71 Transmission Control Module (TCM). Connect a test lamp between the low reference circuit terminal 10 (X2) at the K71 Transmission Control Module (TCM) and the voltage supply component circuit terminal 11 (X2) at the K71 Transmission Control Module (TCM). Command the Clutch PC Solenoid Valve 1 or Increase and Decrease 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 (TCM).

### Component Testing

#### Static Test

1. Ignition OFF, remove the K71 Transmission Control Module (TCM).
2. Test for 5-5.6 Ω at 20°C (68°F) between the low reference circuit terminal 10 (X2) and the voltage supply circuit terminal 11 (X2).

⇒ | If less than the specified range, test the wiring harness for internal short. If the circuit test normal, replace the Q27A Pressure Control (PC) Solenoid Valve.

3. Test for infinite resistance between each terminal and the low reference circuit terminal 10 (X2) and also to the voltage supply circuit terminal 11 (X2).

⇒ | If less than the specified range, replace the wiring harness.

4. If all circuit test normal, perform the Control Solenoid Valve Inspection.

⇒ | If the inspection test normal, replace the control valve body.

### 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