DTC 75. Chevrolet Joy 2008

For 1990-2009 cars

### Circuit Description

The TCM uses the pressure control (PC) solenoid valve in order to regulate the transmission line pressure. The PC solenoid valve consists of an electrical connector, a coil, an armature, a regulating spring, and a poppet valve. The PC solenoid valve is attached to the control valve body. The TCM compares TP voltage fluid temperature, gear states, and other inputs in order to determine the line pressure appropriate for a given load. The TCM regulates the pressure by applying a varying amperage to the PC solenoid valve. The applied amperage varies from 0.1 amps for maximum line pressure to 1.1 amps for minimum line pressure. The TCM then monitors the amperage at the return line.

When the TCM detects a continuous open, short to ground or short to voltage in the PC solenoid valve circuit, then DTC 48 will set.

### Conditions for Running the DTC

• | System voltage between 9.0-18.0 volts.

• | Automatic transmission oil temperature between 0°C (32°F) and 120°C (248°F).

### Conditions for Setting the DTC

Open or short circuit in the line pressure solenoid control circuit.

### Action Taken When the DTC Sets

• | The TCM illuminates the A/T warning lamp when the diagnostic runs and fails.

• | The TCM sets the line pressure solenoid OFF.

• | Line pressure control is set to full throttle.

### Conditions for Clearing the MIL/DTC

The TCM turns OFF the A/T warning lamp when the diagnostic runs and does not fail.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Short to voltage of the signal circuit.

2. Short to ground of the signal circuit.

3. Proper operation of the circuit and component by supplying voltage and a ground.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Automatic Transmission

2

1. Ignition OFF.
2. Disconnect the TCM wiring harness connector.
3. Turn on the ignition, with the engine OFF.
4. Using a DMM, measure voltage at the TCM harness connector terminal 1 to ground.

Is the voltage less than the specified value?

0.3V

Go to Step 3

Go to Step 12

3

1. Ignition OFF.
2. Using a DMM, measure resistance between the TCM harness connector terminal 1 and ground.

Is the resistance greater than the specified value?

500 kohms

Go to Step 4

Go to Step 11

4 | Using a DMM, measure resistance between the TCM harness connector terminals 1 and 2. Is the resistance within the specified value? | 2.6-3.2 ohms | Go to Step 5 | Go to Step 6

5

1. Connect a fused jumper between the TCM harness connector terminal 1 and battery voltage.
2. Connect a fuse jumper wire to TCM harness connector terminal 2 and tap to ground.

Is there a clicking noise coming from the pressure regulator solenoid?

--

Go to Step 7

Go to Step 8

6 | Measure resistance between the TCM harness connector terminals 1 and 2. Is the resistance less than the specified value? | 2.6ohms | Go to Step 9 | Go to Step 10
7 | Replace the TCM. Refer to Transmission Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | --
8 | Replace pressure control solenoid. Did you complete the replacement? | -- | Go to Step 13 | --
9 | Inspect for a short circuit in the pressure solenoid control circuit. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8
10 | Inspect for a short between the pressure solenoid control circuit and the return circuit. Did you and correct the condition? | -- | Go to Step 13 | Go to Step 8
11 | Inspect the pressure solenoid control circuit and return circuit for a short to ground. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8
12 | Inspect the pressure solenoid control circuit and the return circuit for a short to voltage. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8

13

1. Clear the DTCs. Refer to Clearing Transmission Diagnostic Trouble Codes .
2. Start the engine.
3. Operate the vehicle within Conditions for Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK