P0852 Possible Causes
Faulty Park/Neutral Switch
Park/Neutral Switch harness is open or shorted
Poor electrical connection in Park/Neutral Switch circuit
What Does It Mean?
How to Fix Code P0852
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
P0852 Possible Symptoms
Check Engine Light illuminated (or Service Engine Soon warning light)
P0852 Meaning
The Manual Transmission Shift Shaft Switch Assembly, also known as the Internal Mode Switch (IMS), is a sliding contact switch attached to the manual transmission 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) chassis via a short wiring harness. The 5 TCM inputs 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, and to determine transmission shift patterns. The status of each input can be displayed on the scan tool. The five represented input parameters are Signal A, Signal B, Signal C, Signal P (parity), and Signal N (Park/Neutral start signal). 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. The Park/Neutral signal circuit is not internally connected to the TCM; the circuit uses the TCM as an intercommunication connector only. The ECM Park/Neutral diagnostic monitors the Park/Neutral signal circuit for low voltage when the ECM expects to see high voltage and high voltage when the ECM expects to see low voltage.