What this code means
P0315 may mean the PCM does not have the crankshaft variation learn information stored for misfire monitoring.
What the vehicle may do
- The MIL can illuminate.
- Misfire monitoring may be disabled while the learn information is missing.
- The vehicle may require the TLC learn to be completed under the proper driving condition.
Possible fault areas
- An unperformed or unstored TLC learn after PCM work may be involved.
- Related misfire concerns can affect the diagnostic direction.
- Related engine timing concerns can affect the diagnostic direction.
Diagnostic path
Opening context
On this Ram 1500 with the 3.6 Pentastar, P0315 means the PCM does not have the crankshaft variation, or Target Linear Compensation, learned and stored. In plain terms, the PCM may not have the crank reference it uses for misfire monitoring. The MIL can come on, and misfire monitoring may be disabled until the learn is completed. Broadly, this code can point to an unlearned crank variation after PCM work, or to a situation where related misfire or engine timing issues need to be handled before the learn will make sense.
Understand the monitor
The monitor runs continuously with the ignition on. P0315 sets when the PCM is in field mode and the crankshaft position system variation values are not stored in PCM memory. Treat the running and setting information as monitor gates: make sure the conditions that originally set the code can be reproduced, then use the scan tool data to confirm whether the code is current or not.
Record data, clear codes, and see if P0315 returns
First, use the scan tool to read DTCs in all electronic control units and record them. Save a vehicle scan report and the related recorded data so you have the original conditions to work from. Then erase all DTCs. Turn the ignition off for a minimum of 10.0 seconds, turn the ignition back on, and operate the vehicle under the conditions that set the code. After that, read DTCs again. If P0315 does not return, handle it as an intermittent condition. If it does return, continue with the next check.
Check for related code direction
Next, look at the DTCs you recorded. If other misfire or engine timing codes are present, check what they mean first and run the applicable diagnostics for those issues. Do not jump straight into the learn if the PCM is also flagging a timing or misfire problem that could affect the result. If there are no misfire or engine timing DTCs present, move on to the TLC relearn.
Perform the TLC relearn
Now perform the TLC relearn. With the scan tool, first verify that the TLC has not been learned in PCM data under MF TLC Control. Then test drive the vehicle. The PCM learns the TLC, or adaptive numerator, during decel from 113 kph (70 mph) to 73 kph (45 mph) with no brake input. If the PCM completes the TLC Learn procedure, this diagnostic path is complete. If it does not complete, start the process over until the TLC Learn is completed.
Takeaway and CTA
The key on P0315 is to confirm the code is current, clear out any related misfire or timing direction first, and then complete the TLC relearn under the required decel condition. For more diagnostic training, visit stepdiagnostics.com.
Final check
Confirm whether P0315 returns, address related misfire or timing code direction first, then complete the TLC relearn if the path points there.
For more guided automotive diagnostics, visit STEP Diagnostics.
