DTC P1855. Chevrolet Vivant 2005

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Transmission/Transaxle 🢒 Automatic Transmission - ZF 4HP 16 🢒 DTC P1855

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 2 controls the high or low of the line pressure, the flow to each clutch valve, by the operation type, ON/OFF. For example, if solenoid 2 is ON, the line pressure will be low, 599-799 kPa (87-116 psi). If solenoid 1 is OFF, the line pressure will be high, 1 599-1 799 kPa (232-261 psi). Solenoid 2 controls the oil flow to the clutch valve E or the 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 for the vehicle operating conditions.

Conditions for Setting the DTC

•	The solenoid wiring is open.

•	No DTCs P1853 or P1854 are 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.

•	After the ignition is OFF/ON: 3rd gear by hydraulic control. Possible P, R, and N are also possible.

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 P1855 sets, the possible cause of the fault could be solenoid 2.

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check - Automatic Transmission?	--	Go to Step 2	Go to Diagnostic System Check - Automatic Transmission
2	Install the scan tool. Turn the ignition ON, with the engine OFF. Select Actuating on the scan tool. Actuate solenoid 2 ON/OFF. Does the solenoid 2 change ON/OFF?	--	Go to Diagnostic Aids	Go to Step 3
3	Turn the ignition OFF. Disconnect the transaxle wiring connector. Measure the resistance between terminals 3 and 12 of the transaxle wiring connector. Is the resistance within the specified values?	6 ohms	Go to Step 7	Go to Step 4
4	Remove the oil pan. Disconnect the wiring connector of solenoid 2. Measure the resistance between terminal 1 of solenoid 2 and terminal 13 of the transaxle connector. Measure the resistance between terminal 2 of solenoid 2 and terminal 3 of the transaxle connector. Is the resistance within the specified value?	0 ohms	Go to Step 6	Go to Step 5
5	Repair the line between terminal 1 and terminal 13 for an open. Repair the line between terminal 2 and terminal 3 for an open. Did you complete the repair?	--	System OK	--
6	Replace the solenoid 2. Did you complete the replacement?	--	System OK	--
7	Disconnect the transaxle wiring connector and transmission control module (TCM) connector. Measure the resistance between terminal 3 of the transaxle wiring connector and terminal C8 of the TCM wiring connector. Measure the resistance between terminal 13 of the transaxle wiring connector and terminal A9 of the TCM wiring connector. Is the resistance within the specified value?	0 ohms	Go to Step 9	Go to Step 8
8	Repair the transaxle wiring harness for an open. Did you complete the repair?	--	System OK	--
9	Replace the TCM. Refer to Transmission Control Module Replacement Did you complete the replacement?	--	Go to Step 10	--
10	Clear the DTCs with a scan tool. Road test the vehicle. Observe the DTC information with a scan tool. Are there any DTCs displayed that have not been diagnosed?	--	Go to Step 2	System OK