ā¢ | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
ā¢ | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
ā¢ | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Park/Neutral Signal | P0850/P0851 | P0850/P0852 | P0850/P0852 | -- |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: 12 Volts = In-Gear, 0 Volts = Park/Neutral | |||
Park/Neutral Signal | Park/Neutral | In-Gear | In-Gear |
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 5 inputs to the TCM from the transmission manual shift shaft switch assembly indicate the transmission gear selector lever position. This information is used for engine start enable, engine controls as well as determining the transmission shift patterns. The state of each input is available for display on the scan tool. The five input parameters represented are Signal A, Signal B, Signal C, Signal P (Parity), and Signal N (Park/Neutral Start Signal). Park/Neutral Signal is sent from the Park/Neutral switch directly to the Engine Control Module (ECM) and is used for engine start enable. The Park/Neutral Signal circuit is not connected to the TCM internally. The circuit uses the TCM as a pass-through connector only. The ECM Park/Neutral diagnostic monitors the Park/Neutral signal circuit to detect low voltage when the ECM expects high voltage and high voltage when the ECM expects low voltage.
ā¢ | Ignition voltage is between 8-18 volts. |
ā¢ | Engine speed is greater than 1000 RPM. |
ā¢ | The ECM detects the Park/Neutral switch signal equals 0 volts (Park/Neutral) when the IMS reports a Drive range for 0.2 second. |
ā¢ | TP is equal to or greater than 10 percent. |
ā¢ | Engine torque is equal to or greater than 75 NĀ·m (55 lb ft). |
ā¢ | Vehicle speed is equal or greater than 10 km/h (6 mph). |
The ECM detects the Park/Neutral switch signal equals 12 volts (In-Gear) when the IMS reports a Park/Neutral range for 0.2 second.
ā¢ | DTCs P0850, P0851, and P0852 are Type C DTCs. |
ā¢ | The ECM uses IMS Range for engine start-up. |
DTCs P0850, P0851, and P0852 are Type C DTCs.
Automatic Transmission Controls Schematics
Electronic Component Description
ā¢ | Circuit Testing |
ā¢ | Wiring Repairs |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
DT-48616-10 Adapter Harness
ā | If not the specified value, refer to Range Selector Lever Cable Adjustment. |
ā | If greater than the specified range, test the ground circuit for an open/high resistance. |
ā | 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. |
ā | If greater than the specified range, test the shaft position switch assembly. Refer to Component Testing. If the shaft position switch assembly tests normal, replace the control solenoid (w/body and TCM) valve assembly. |
ā | If not the specified value, test the shaft position switch assembly, refer to Component Testing. If the switch assembly test normal, replace the control solenoid (w/body and TCM) valve assembly. |
ā | If greater than the specified range, replace the shaft position switch assembly. |
ā | If not the specified value, replace the shaft position switch assembly. |
Note:
ā¢ | Perform the Service Fast Learn Adapts following all transmission related repairs. |
ā¢ | Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
ā¢ | Control Module References for ECM or control solenoid (w/body and TCM) valve assembly replacement, setup, and programming |