P0315 relearn procedure is a function you must perform after replacing/repairing a crankshaft position (CKP) sensor. P0315 DTC shows up when there is data collected by CKP that is not present in the memory of the powertrain control module PCM. So P0315 relearn refers to the CKP sensors’ relearn process.
As a tech-savvy guy when you saw P0315 DTC (diagnostic trouble code) on the OBD scanner, you tracked down the issue and replaced your faulty crankshaft position sensor. Still, you are not getting the expected result and you find out you have to perform a relearning procedure.
So what is P0315 relearn procedure?
Whether you have a scanner or not, we will walk you through the relearn procedure step by step. It’s a fairly simple process, so let’s jump in.
Source: Honda Parts Online Dot Net
What Does P0315 Relearn Mean?
P0315 relearn means the crankshaft position sensor recalibration. This DTC code shows up due to a fault in the crankshaft position system. Relearn procedure is done after a crankshaft replacement.
P0315 code is a generic DTC code that shows up on your scanner and it means “Crankshaft Position System Variation Not Learned.” This sensor monitors the rotation of the crankshaft and sends information to PCM. (0)
The relearning procedure may vary from engine to engine. Check if your code reader or scanner has a relearn function for the CKP sensor.
SummaryP0315 relearn is a function you need to perform after replacing a faulty crankshaft position sensor.
How to Relearn P0315 Using a Scanner?
Relearn procedure duration depends on the vehicle and the scanner you are using. With some basic mechanical knowledge, you can perform the procedure yourself. P0315 relearn procedure can take a few minutes to an hour.
P0315 Relearn Procedure For GM Vehicles
So this relearn procedure applies to all GM vehicles including Chevy.
Step 1: Plug in the scan tool on the Data Link Connector (DLC) located under the dash. Apply the parking brake and block the wheels and make sure the hood is closed.
Step 2: For automatic transmission put it in park mode. If you have a manual transmission, put it in neutral mode.
Step 3: Turn the engine on and make sure it is at the operating temperature of 158°F.
Step 4: Apply and hold the brake pedal. Then select and enable the Crankshaft Variation Relearn Procedure or CASE learn on the scan tool.
Step 5: Now speed up the engine to 4,000 rpm gradually (or instructed rpm for your engine). Hold this rpm until the engine speed drops back toward idle. After the relearning procedure, release the throttle promptly. The scan tool will show a successful relearn.
[Note: Usually, for inline 4-cylinder GM vehicles, the RPM cutoff value is 3970 RPM, and for V8 engines, it’s 4000 RPM. A GM passenger car with a V6 has a cutoff value of 5150 RPM whereas, for light-duty trucks, it’s 4000 RPM.]
Step 6: Turn the engine off for at least 15 seconds. Disconnect the scan tool. If the relearn procedure is not successful, then another trouble code DTC P1336 will appear.
Step 7: DTC P1336 is a manufacturer-specific trouble code similar to P0315. If DTC P1336 is present, ensure that the CKP procedure was followed carefully. If this does not work, consult a mechanic.
Source: SVT performance
P0315 Relearn Procedure for Ford Vehicle
This relearn procedure is done using an HP tuner on a ford vehicle. Make sure your engine operating temperature is 176°F.
Step 1: Connect the HP tuner to your vehicle and start the scanner.
Step 2: Check the DTC menu on the scanner and clear all trouble codes.
Step 3: Go to the input-output option on the scanner. Then, select the crank relearn procedure. Make sure your parking brake is set with the transmission in park or neutral.
Step 4: Start the car and wait a few seconds. Then speed up to 4500 RPM.
Step 5: “Crank relearn successful” will appear on your scanner. Unhook the tuner and turn off your engine.
P0315 Relearn Procedure: Common
The generic crankshaft relearning procedure is similar to the ones mentioned above except there will be a small disparity from model to model. The operating temperature of engine oil and coolant will differ from vehicle to vehicle as well. Other than that all the steps are similar.
The common precaution before you perform this procedure is to check your engine coolant and oil level. At the same time, check your vehicle’s RPM cutoff value. You are not supposed to accelerate above the instructed cutoff value.
How to Relearn P0315 Without a Scanner?
When the relearn function is not accessible from your scanner follow this method.
This is how to do a crankshaft relearn without a scanner
Step 1: Turn off all components like AC, radio, etc. then start the engine. Keep the car idle in either park or in the neutral mode for at least two minutes. Make sure the engine coolant temp and the air temperature sensor temperatures are within 5 degrees F of one another.
Step 2: Gradually accelerate the vehicle to 55 mph at part throttle. Keep going at 55 mph for approximately ten minutes. Then check to make sure that the engine has reached the operating temperature. The usual engine operating temperature is around 195 to 220 degrees Fahrenheit.
Step 3: Run your engine at 55 mph for another five minutes at the operating temperature.
Step 4: Slowly decrease the speed to 45 mph without using the brakes. Keep going at 45 mph for a minute.
Step 5: Complete four deceleration cycles like the one mentioned above. So in each cycle;
- Run the engine at 55 mph then decelerate to 45 mph in 25 seconds.
- Wait for 15 seconds when you are at 45 mph speed
Step 6: After completing the four cycles in step 5, speed up to 55 mph and cruise for two minutes.
Step 7: Stop the vehicle and idle for two minutes with the brake applied. Put the transmission in Drive or Neutral while repressing the clutch.
Crankshaft position sensors go bad over time due to exposure to high temperatures and faulty circuitry. Usually, these sensors last as long as the vehicle. Check your CKP sensor with a multimeter after 100,000 miles.
Is It Necessary to Relearn P0315?
Yes, it is necessary to relearn P0315 when you have replaced the crankshaft position sensor. Most of the time, this DTC comes up due to the CKP sensor failure. This sensor fails because of electrical issues such as wiring damage, burnt connectors, etc.
What Happens If I Ignore P0315?
If you ignore P0315 then your vehicle will run poorly or might even go into limp mode. Engine misfire, backfire, rough idling, and stalling will happen if you run the vehicle with this DTC code. At the same time, your fuel consumption will be higher.
Can P0315 Cause No Start?
Yes, P0315 can cause no start. When the communication between the PCM and CKP sensor is disrupted, it can lead to a no-start.
Do I Need To Relearn Crankshaft Position Sensors?
Yes. You need to relearn the crankshaft position sensor. Without relearning procedure your vehicle will have issues like engine stalling, misfiring, backfiring, and high fuel consumption.
Will Disconnecting Battery Reset Crankshaft Sensor?
Disconnecting the battery won’t reset the crankshaft sensor. You must perform the relearn procedure for your crankshaft position sensor.
Hopefully, this article assisted you with the P0315 relearn procedure. Even though it is slightly different for every car, you get the idea of the whole relearning process now.