Cruze

DTC P0850-P0852

The transmission manual shift shaft switch assembly, also known as the internal mode switch (IMS), is a sliding contact switch attached to the manual shift shaft inside the transmission case. The park/neutral position (PNP) switch is integrated into the IMS and connects to the transmission control module (TCM) lead-frame through a short wire harness. The park/neutral signal circuit uses the TCM as a pass-through connector only. The TCM provides the low reference circuit to the PNP switch.

The Park/Neutral Signal is sent from the park/neutral switch directly to the engine control module (ECM) and is used for engine start enable.

P0850 and P0851

P0852

The ECM detects the park/neutral switch signal equals 12 volts, In-Gear, when the IMS reports a park/neutral range for 0.2 seconds.

DTCs P0850, P0851, and P0852 are Type C DTCs.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Component Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

DT-48616-10 Adapter Harness

For equivalent regional tools, refer to Special Tools .

1. If there are any other transmission DTCs set, diagnose those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
2. Ignition ON, observe the scan tool ECM Park/Neutral switch parameter while moving the gear lever from Park and through all ranges. The parameter should display Park/Neutral when in Park or Neutral and In-Gear when in Reverse or Drive.
3. Observe the scan tool TCM IMS parameter while slowly moving the gear lever from Park through all ranges. Verify the gear position matches the scan tool parameter.

⇒	If not the specified value, refer to Range Selector Lever Cable Adjustment .

4. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections .

Note: You must perform the Circuit/System Verification first.

1. Ignition OFF, disconnect the 14-way harness connector at the transmission.
2. Install the DT-48616-10 harness to the 14-way harness connector to the engine harness.
3. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

4. Ignition ON, engine OFF, test for 11-13 volts between the adaptor harness terminal 3 and ground.

⇒	If not within the specified range, test the park/neutral signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

5. Ignition OFF, disconnect the DT-48616-10 harness from the vehicle harness connector.
6. Remove the transmission control valve body cover. Refer to Control Valve Body Cover Replacement .
7. Connect the vehicle harness connector to the control solenoid valve assembly.
8. Disconnect the automatic transmission internal mode switch electrical connector from the TCM.
9. Ignition ON, engine OFF, test for 11-13 volts between terminal A on the TCM and ground at the transmission case.

⇒	If not within the specified range, replace the control solenoid valve assembly.

10. Connect a 3A fused jumper wire between the IMS connector terminal A and ground. Verify with a scan tool the Park/Neutral Position Switch parameter changes from In Gear to Park/Neutral when connected to ground.

⇒	If not the expected results, test the signal circuit for an open/high resistance or a short-circuit to ground or voltage. If circuit tests normal, replace the ECM.

11. If all circuits test normal, replace the automatic transmission internal mode switch.

Note: 

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.