P0918Generic code

P0918 Code: Gear Shift Position Circuit Intermittent

The P0918 code means the gear shift position sensor signal is cutting out or jumping intermittently. The main effect is that the transmission does not know where its mechanism is. Reproduce the fault by moving the harness while watching live data.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$60 to $800
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0918 code means

Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual clutch transmissions use electric or hydraulic actuators to disengage the clutch, to choose the gear plane (select) and to engage the gear (shift). The transmission computer watches every actuator with position sensors. The shift sensor reports whether a gear is engaged or the transmission is in neutral.

The sensor gets a 5 volt reference and a ground from the computer and sends back a signal between about 0.5 and 4.5 volts. Intermittent dropouts, which is what the P0918 code reports, almost always come from a poor contact or a damaged wire.

If its signal fails, the computer cannot confirm that the gear went in and switches to limp mode. After any repair of these components you must run the transmission relearn procedures with a scan tool (clutch touch point, select and shift positions). Without them the transmission will not work properly.

Intermittent faults are found by reproducing them. With the engine running and the scan tool in graphing mode, move the harness section by section, tap the connector gently and, if needed, warm the area with a hair dryer or spray the connector with water. The spot where the reading jumps is where the fault is.

P0918 code symptoms

  • Check engine light on.
  • The transmission does not recognize the position of its mechanism.
  • The transmission does not go into gear or stays in neutral.

Likely causes of the P0918 code

  1. Poor contact in the connector. Pins that are loose or backed out.
  2. Wire broken inside its insulation, which opens the circuit with vibration.
  3. Harness rubbing against moving or hot parts.
  4. Sensor with an intermittent fault, often related to temperature.

How to diagnose the P0918 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check supply and ground with the key on: the reference should be correct and the ground voltage drop under 0.1 volts.
  4. Measure the signal with the connector attached and see whether it changes with the condition.
  5. Do a wiring wiggle test with the scan tool in graphing mode.
  6. Check the continuity of each wire to the computer (under 1 ohm).
  7. Run the transmission relearn procedures after the repair.

How to fix the P0918 code

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

Technical reference data

  • 5 volt reference, ground and a signal of 0.5 to 4.5 volts (or a contactless Hall effect sensor).
  • Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

This code is very common on automated manual transmissions. On many hydraulic systems the actuator fluid is a specific type and the reservoir should be checked regularly.

P0918 on Opel

Very common on the Opel Easytronic.

P0918 on Fiat

Very common on the Fiat Dualogic.

P0918 on Toyota

Very common on the Toyota MMT.

P0918 on Smart

Seen on Smart vehicles with an automated manual transmission.

P0918 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0918

Can I drive with a P0918 code?
With caution. The transmission can be left without gears.
Do I have to replace the sensor?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor does.
What does the gear shift position sensor do?
Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual clutch units use electric or hydraulic actuators to release the clutch, select the gear plane and engage the gear. The computer watches each actuator with position sensors. The shift sensor reports whether a gear is engaged or the transmission is in neutral.
How much does it cost to fix P0918?
As a rough guide, between $60 and $800. Most of the labor goes into finding the intermittent spot, and a new sensor costs more.
What does the P0918 code mean?
The P0918 code is a generic OBD2 code that means the gear shift position sensor signal is dropping out or jumping intermittently.
Will a P0918 code clear itself?
The light may go out after clean drive cycles, but the weak contact is still there and the code will return when it opens again.
What is the most common cause of P0918?
A poor contact in the connector. A wire broken inside its insulation and a harness that rubs follow.

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