P0853 Code: Drive Switch Input Circuit

What the P0853 code means

Some transmissions have a switch that confirms the shift lever is in D. The computer compares its signal with the transmission range sensor.

It is a simple switch, so the computer sees either a high or a low voltage depending on its position. The P0853 code is set when something is wrong with that circuit, and the cause can be the switch, the wiring or the power supply.

When the signal fails, the transmission can go into limp mode or refuse certain gears. The transmission range sensor is tested the same way, so check it as well.

Always start with the simplest things: fuse, relay and connector. Then check power, ground and signal with the component plugged in (using back-probes), and finally the continuity of each wire to the computer. Only replace the switch when everything else checks out.

P0853 code symptoms

• Check engine light on.
• Transmission in limp mode.

Likely causes of the P0853 code

1. Damaged or corroded connector. This is the most frequent cause.
2. Wiring cut or shorted between the switch and the computer.
3. Bad switch, open or shorted inside.
4. Missing power reference. Check whether other sensors are also failing.
5. Computer. This is uncommon, so rule out everything above first.

How to diagnose the P0853 code step by step

1. Read the switch value on the scan tool and compare it with what you expect.
2. Inspect the connector for corrosion, water or loose pins.
3. Check power and ground with the key on: the reference should be correct and the ground voltage drop should be under 0.1 V.
4. Measure the signal with the connector plugged in and see whether it changes with the lever position.
5. Do a wiggle test on the harness with the scan tool in graph mode.
6. Check continuity of each wire to the computer (under 1 ohm).

How to fix the P0853 code

• Repair the connector or the wiring.
• Replace the switch if the tests confirm it is bad.
• Correct the real condition if there is one.
• Clear the codes and verify with a road test.

Technical reference data

• The switch or sensor is powered from the computer. Check the values in the service manual.
• Reference values are only a guide, so look up the manufacturer data for your vehicle.
• Wire continuity should be under 1 ohm, and ground voltage drop under 0.1 V.

Brand-specific notes

The letter assignment and the location of the component change from one manufacturer to another, so check the manual for your vehicle before you start testing.

A P0853 code is easier to read when you compare the Drive switch with the range sensor on the scan tool. If the two disagree about the lever position, you have found the side that is lying.

Frequently asked questions about P0853