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Error Code P1309 is defined as Misfire Detection Monitor Not Enabled. This code means there is too much variance in speed of the firing of the cylinders, causing the misfire detector to be disabled.
This error code is a manufacturer-specific trouble code, meaning it does not apply to all vehicles equipped with OBD-II system or vehicles made since 1996 up to present. Rather, it applies to select manufacturers, such as Ford. Specifications on the definition, troubleshooting, and repairs still vary from one manufacturer to another.
Error Code P1309 means the misfire detection monitor system is disabled. It is detected when the PCM (powertrain control module, also known as ECM or engine control module) disabled the misfire monitor. In simpler terms, this means the PCM is running too rough to pinpoint which cylinder is misfiring. This causes the misfire detector to be disabled. This is usually caused by the signal generated by the CMP (camshaft position) sensor by sensing the passage of teeth from the CMP wheel.
As with other error code, this code activates the Check Engine light and registers the code to the system. In some cases, vehicles may show drivability issues, such as:
- Hesitation upon acceleration
- Poor acceleration
- Rough idle
There are many possible causes for this code to arise, some of the common causes are:
- Defective Camshaft Position Sensor
- Improper installation of the Synchronize Assembly
- Defective PCM
- Incorrect input sensor parameters
How to Check
If you have one cylinder that is missing badly, then this code will arise.
To diagnose, check the CMP sensor. This requires basic tools such as multimeter and some knowledge on diagnosis, thus, if you’re not sure, you can get the help of a professional technician. Also, Make sure you also check the continuity of the wiring harness connector around the sensor.
Check the PCM.
How to Fix
Repairs for this code include:
- Replacement of the CMP sensor
- Proper installation of the synchronizing assembly
- Replacement of PCM
- Correct input sensor parameters
In many cases, replacing the CMP (camshaft position) sensor usually fixes the problem, but if the sensor is installed out of synchronization, it will cause the Error Code P1309.
If the CMP is correctly installed, replace the PCM and restore the vehicle. Then rerun Quick Test.