P0805Generic code

P0805 Code: Clutch Position Sensor Circuit

The P0805 code means there is an electrical fault in the clutch position sensor circuit. The main effect is a clutch the computer cannot control, or a start-stop system that is turned off. Check the connector and wiring first, because they fail as often as the sensor.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$60 to $600
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0805 code means

On automated manual transmissions and on some vehicles with start-stop, a sensor measures the exact position of the clutch (or of the pedal). The computer uses it to control how the clutch engages, or to know when to restart the engine.

The sensor receives a 5 V reference and a ground from the computer and returns a signal of roughly 0.5 to 4.5 V. A circuit fault, the P0805 code, can come from the sensor, the wiring or the power supply.

If the signal fails, the automated transmission cannot control the clutch and goes into limp mode, or the start-stop system stops working.

Always start with the simplest items: fuse, relay and connector. Then check power, ground and signal with the component connected (using back-probes), and finally the continuity of each wire up to the computer. Only if all of that is good should you replace the component.

P0805 code symptoms

  • Check engine light on.
  • Clutch not controlled, or start-stop disabled.

Likely causes of the P0805 code

  1. Damaged or corroded connector. The most frequent cause.
  2. Wiring cut or shorted between the sensor and the computer.
  3. Failed sensor, open or shorted internally.
  4. Missing power reference. Check whether other sensors are also failing.
  5. Computer. Uncommon; rule out everything above first.

How to diagnose the P0805 code step by step

  1. Read the sensor value on the scan tool and compare it with what is expected.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check power and ground with the key on: a correct reference and less than 0.1 V of drop on the ground.
  4. Measure the signal with the connector plugged in and see whether it changes with the condition.
  5. Do the wiggle test on the harness with the scan tool in graphing mode.
  6. Check the continuity of each wire up to the computer (under 1 ohm).
  7. Run the clutch touch point relearn after the repair, if it is an automated manual transmission.

How to fix the P0805 code

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

Technical reference data

  • 5 V reference, ground and a signal of 0.5 to 4.5 V.
  • These are approximate values: check the manufacturer data for your vehicle.

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.

Frequently asked questions about P0805

What does the P0805 code mean?
It is a generic OBD2 code that means there is an electrical fault in the clutch position sensor circuit. The cause can be the sensor, its wiring or its power supply.
Can I drive with a P0805 code?
Yes, with caution. With a P0805 code an automated manual transmission may go into limp mode, or the start-stop system may stop working, so keep trips short until it is repaired.
Does the sensor have to be replaced?
Only if the tests confirm it. The connector and the wiring fail just as often.
What does the clutch position sensor do?
On automated manual transmissions and on some vehicles with start-stop, a sensor measures the exact position of the clutch (or of the pedal). The computer uses it to control how the clutch engages or to know when to restart the engine.
How much does it cost to fix P0805?
As a rough guide, between $60 and $600.
Will a P0805 code clear itself?
It can go out if the connection was only loose or damp for a moment. A damaged connector, wire or sensor will bring it back.
What is the most common cause of P0805?
A damaged or corroded connector. Check it and the wiring before you buy a sensor.

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