P0727Generic code

P0727 Code: Engine Speed Input Circuit No Signal

The P0727 code means there is a complete loss of signal from the engine speed input signal to the transmission computer. The main effect is lower shift quality.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$20 to $300
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0727 code means

The transmission computer needs to know the engine speed to work out torque converter slip and shift quality. It receives it over a dedicated wire or over the CAN network from the engine computer.

The signal consists of pulses whose frequency depends on the speed or the quantity being measured. Without pulses, the computer cannot calculate the quantity and uses a substitute value. That is what sets the P0727 code.

If this signal fails, the transmission loses an important reference. Shifts can get worse and the torque converter may stop locking up. If communication (U) codes are stored, resolve them first.

First check that the sensor is getting power and ground. Then, with the component moving, measure the signal with an oscilloscope or a multimeter on the frequency scale. If there are no pulses with correct power, the sensor is bad. If there are pulses at the sensor but not at the computer, the wire is cut.

P0727 code symptoms

  • Check engine light on.
  • Lower shift quality.

Likely causes of the P0727 code

  1. Sensor without power, from a fuse or the reference.
  2. Signal wire cut between the sensor and the computer.
  3. Failed sensor that does not generate pulses.
  4. Damaged or dirty reading element, with broken or dirty teeth.

How to diagnose the P0727 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 and loose pins.
  3. Check power and ground with the key on: a correct reference and less than 0.1 volt drop on the ground.
  4. Measure the signal with the connector plugged in and see whether it changes with the condition.
  5. Do a wiggle test of the wiring with the scan tool in graph mode.
  6. Check the continuity of each wire back to the computer (under 1 ohm).
  7. Check for communication (U) codes in the engine and transmission modules before you chase wiring.

How to fix the P0727 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the P0727 code and verify with a road test.

Technical reference data

  • Pulse signal or CAN message.
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

The source reports this code as frequent on vehicles with separate computers for the engine and the transmission.

P0727 on Chrysler

Frequent on Chrysler vehicles with separate engine and transmission computers.

P0727 on Ford

Frequent on Ford vehicles with separate engine and transmission computers.

Frequently asked questions about P0727

What does the P0727 code mean?
It means the computer sees a complete loss of signal from the engine speed input signal to the transmission computer.
Can I drive with a P0727 code?
Yes, with caution. Shifts may get rougher and the torque converter may stop locking up.
Do I have to replace the sensor?
Only if the tests confirm it. The connector and the wiring fail just as often.
What does the engine speed input do for the transmission?
The transmission computer needs the engine speed to work out torque converter slip and shift quality. It gets it over a dedicated wire or over the CAN network from the engine computer.
How much does it cost to fix P0727?
As a rough guide, between $20 and $300, depending on whether it is a connector, wiring or a new sensor.

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Questions about the P0727 code

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