A trouble code P0715: Mainshaft Speed Sensor Malfunction usually tells you that the transmission is slipping due to an internal mechanical problem (usually cause by wear and tear).
NOTE: The mainshaft speed sensor is called the transmission input speed sensor.
In this tutorial, I'll shed some light on what this trouble code means and some of the tests you can perform to find its cause (and solution).
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Honda Accord (DX, EX, LX): 1995, 1996, 1997.
- 2.2L Honda Odyssey: 1995, 1996, 1997.
What Does Trouble Code P0715 Mean?
A trouble code P0715: Mainshaft Speed Sensor Malfunction lets you know that there is an irregular transmission countershaft to mainshaft speed difference.
In plain English, this means that the speed of the transmission's output shaft (countershaft) and the speed of the transmission's input shaft (mainshaft) is not within the programmed parameters.
This difference in speed between these two sensors is a good indicator that the fuel injection computer sees the automatic transmission 'slipping'.
Common Symptoms Of A P0715 Trouble Code
You're gonna' see one or more of the following symptoms:
- The check engine light is on.
- Harsh transmission shifts.
- Transmission slips when you accelerate the engine (with the transmission in Drive).
What Causes A P0715 Trouble Code?
In 9 of 10 cases, a trouble code P0715 is caused by an internal mechanical problem in the transmission (causing it to slip).
In the majority of cases (if not all), this is caused by normal wear and tear (I usually see this trouble code in vehicles with over 150,000 miles).
In some rare instances, this trouble code is caused by a defective transmission input speed sensor (mainshaft speed sensor) or a transmission output speed sensor (countershaft speed sensor).
Now in case you're wondering what 'slipping' means, it refers to stepping on the gas pedal to accelerate the vehicle, but the transmission does not move the vehicle as the engine revs up (feels like the engine is disconnected from the transmission).
Diagnosing A P0715 Trouble Code
I recommend testing the transmission input speed sensor and the transmission output speed sensor before concluding that the transmission is kaput.
Both sensors can be easily tested with a multimeter resistance test that you can do yourself.
You can find the input (mainshaft) and output (countershaft) speed sensor tests here:
- How To Test The Input Speed Sensor (1995-1997 2.2L Accord And Odyssey).
- How To Test The Output Speed Sensor (1995-1997 2.2L Accord And Odyssey).
If both sensors pass their resistance test, then you can conclude that the transmission has an internal mechanical problem that requires an overhaul or replacement.
More 2.2L Honda Accord Tutorials
You can find a complete list of 2.2L Honda tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The MAP Sensor (1994-1997 2.2L Accord, Odyssey, Prelude).
- How To Test The Head Gasket (1992-1997 2.2L Accord, Odyssey, Prelude).
- How To Test The Engine Compression (1992-1997 2.2L Accord, Odyssey, Prelude).
- How Often Should I Replace The Spark Plugs? (2.2L Honda Accord).
If this info really saved the day, buy me a beer!