GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Vivant 🢒 HVAC 🢒 HVAC - Automatic 🢒 DTC P1873

Circuit Description

The pressure control solenoid (PCS) valve 3, 4, 5, 6, is a precision electronic pressure regulator that controls the operations of each clutch, brake, and lock-up clutch.

The valve reduces the system pressure with which the downstream solenoid valves and electrical pressure regulating valves are charged. It is possible to use smaller solenoid valves as a result. The PCS requires a constant input pressure.

Conditions for Setting the DTC

DTC P1874 is not set.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will illuminate.
    • The TCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.
    • Adopt Emergency/Substitute Mode and constant 4th gear.
    • The power supply is cut off to the PCS valve.

Conditions for Clearing the MIL/DTC
    • The MIL will turn OFF when the malfunction has not occurred after 3 ignition cycles.
    • A history DTC will clear after 40 consecutive warm-up cycles without a fault.
    • Using a scan tool can clear history DTCs.

Diagnostic Aids

When DTC P1873 sets, the repair of the solenoid valve power supply line is recommended.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install the scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Start the engine and allow it to warm up at idle.
  4. Put the gear selector in Park, Neutral, and set the parking brake.
  5. Observe solenoid 1, 2 on the scan tool.

Is the solenoid ON?

--

Go to Diagnostic Aids

Go to Step 3

3
  1. Turn the ignition to LOCK.
  2. Disconnect the transaxle wiring connector and the transaxle control module (TCM) connector.
  3. Measure the resistance between terminal 3 of the transaxle wiring connector and C8 of the TCM wiring connector.

Is the resistance within the values shown?

0 ohms

Go to Step 5

Go to Step 4

4

Repair the circuit for a short to ground and an open.

Is the action complete?

--

System OK

--

5
  1. Remove the oil pan.
  2. Disconnect the solenoid wiring connector.
  3. Measure the resistance between terminal 3 of the transaxle wiring connector and 2 of the solenoid 1 wiring connector.

Is the resistance within the specified value?

0 ohms

Go to Step 7

Go to Step 8

6

Repair the circuit, power supply lines, for a short to ground and an open.

Is the action complete?

--

System OK

--

7

Replace the TCM.

Is the action complete?

--

Go to Step 8

--

8
  1. After the repair, use a scan tool clear info function and road test the vehicle.
  2. Review the DTC info.

Has the last test failed or is the current DTC displayed?

--

Go to Step 2

System OK