On four-wheel-drive vehicles that are equipped with an automatic transmission, the drive switch tells the ECU what gear the transfer case has been shifted into. This information is necessary to calculate the correct shift timing and engine setup. If an incorrect voltage signal is being sent from the transmission drive switch input circuit, a P0853 DTC will be stored.
How Serious is the Code?
Because the vehicle’s computer needs to know what the transfer case is doing, a P0853 diagnostic trouble code is very serious and can impact the drivability of the vehicle.
Symptoms of a P0853 include:
- Four-wheel-drive system refuses to engage
- Transmission shifts harshly
- Transmission will not shift
- Damage to the wiring and/or connectors
- Failed drive switch
- Failed transfer case range sensor
How to Diagnose the Code?
The first step to diagnosing a P0853 OBDII trouble code, is to check the condition of the wiring and connectors. If no problems are found, the voltage output and grounding of the driver switch itself will need to be checked. Should no issues be found, transfer case range sensor will need to be tested and possibly adjusted.
What Repairs Will Fix P0853?
- Repair or replace damaged wiring and connectors
- Replace drive switch
- Adjust transfer case range sensor
- Replace transfer case range sensor
- P0850 – Park/Neutral Switch Input Circuit
P0851 – Park/Neutral Switch Input Circuit Low
P0852 – Park/Neutral Switch Input Circuit High
P0854 – Drive Switch Input Circuit Low