GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Optra 🢒 Transmission/Transaxle 🢒 Automatic Transmission - ZF 4HP 16 🢒 DTC P1852

Circuit Description

The shift solenoids are 2 identical, normally open electronic exhaust valves that control upshifts and downshifts in all forward gear ranges. These shift solenoids work together in a combination of ON and OFF sequences to control the line pressure and shift mechanisms, such as clutches and brakes.

Solenoid 1 controls the high or low of the line pressure, the flow to each clutch valve, by the operation type ON/OFF. For example, solenoid 1 is ON, line pressure will be low, 599-799 kPa (87-116 psi) (6-8 bar). Solenoid 1 is OFF, line pressure will be high, 1 599-1 799 kPa (232-261 psi) (16-18 bar). Solenoid 2 controls the oil flow to clutch valve E or lock-up clutch valve by the ON/OFF signal.

The transmission control module (TCM) monitors numerous inputs to determine the appropriate solenoid state combination and transaxle gear tor the vehicle operating conditions.

Conditions for Setting the DTC
    • Solenoid wiring open
    • No DTC P1850, P1851.
    • Immediately after the above condition occurs

Action Taken When the DTC Sets
    • The hold lamp will blink.
    • 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 by hydraulic control.
    • After ignition OFF/ON: 3rd gear by hydraulic control. Possible P, R, and N also possible.

Conditions for Clearing the Hold Lamp/DTC
    • The hold lamp 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 P1852 sets, the possible cause of the fault could be solenoid 1.

Step

Action

Values

Yes

No

1

Perform the Diagnostic System Check.

Is the check complete?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2
  1. Install the scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Select Actuating on the scan tool.
  4. Actuate solenoid 1 ON/OFF.

Does the solenoid 1 change ON/OFF?

--

Go to Diagnostic Aids

Go to Step 3

3
  1. Turn the ignition OFF.
  2. Disconnect the transaxle wiring connector.
  3. Measure the resistance between terminals 3 and 12 of the transaxle wiring connector.

Is the resistance within the specified value?

TFT 25°C (77°F)

6 ohms

Go to Step 7

Go to Step 4

4
  1. Remove the oil pan.
  2. Disconnect the wiring connector of solenoid 1.
  3. Measure the resistance between terminal 1 of solenoid 1 and terminal 12 of the transaxle wiring connector.
  4. Measure the resistance between terminal 2 of solenoid 1 and terminal 3 of the transaxle wiring connector.

Is the resistance approximately equal to the specified value?

0 ohms

Go to Step 6

Go to Step 5

5
  1. Repair the line between terminal 1 and terminal 12 for an open.
  2. Repair the line between terminal 2 and terminal 3 for an open.

Is the repair complete?

--

System OK

--

6

Replace solenoid 1.

Is the replacement complete?

--

System OK

--

7
  1. Disconnect the transaxle wiring connector and the transmission control module (TCM) connector.
  2. Measure the resistance between terminal 3 of the transaxle wiring connector and terminal C8 of the TCM wiring connector.
  3. Measure the resistance between terminal 12 of the transaxle wiring connector and terminal A9 of the TCM wiring connector.

Is the resistance approximately equal to the specified value?

0 ohms

Go to Step 9

Go to Step 8

8

Repair the transaxle wiring harness for an open.

Is the repair complete?

--

System OK

--

9

Replace the TCM. Refer to Transmission Control Module Replacement .

Is the replacement complete?

--

Go to Step 10

--

10
  1. After the repair, use a scan tool Clear Info function.
  2. Road test the vehicle.
  3. Review the DTC info.

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

--

Go to Step 2

System OK