What this code means
P16E2 may mean the PCM is not seeing expected communication on the alternator LIN communication circuit.
What the vehicle may do
- The vehicle may show charging-system behavior.
- The fault may be intermittent.
- The code may return only when the original operating conditions are duplicated.
Possible fault areas
- Loose or poor alternator connections may be involved.
- The alternator positive terminal may be involved.
- The LIN wiring between the alternator and PCM may be involved.
- The battery sensor side of the circuit may be involved.
- The alternator, PCM, or PCM software may be involved depending on the test path.
Diagnostic path
Opening context
On this Honda CR-V, P16E2 points to a possible PGM-FI to alternator LIN communication problem. In plain terms, the PCM may not be seeing the alternator communication the way it expects. The vehicle may show charging-system behavior, may store the code intermittently, or may only show the fault under certain operating conditions. The broad areas to keep in mind are the alternator connection, the alternator +B terminal, the LIN wiring between the alternator and PCM, the battery sensor side of the circuit, and in some paths the PCM or PCM software. Before going deep, check the alternator +B terminal. If that terminal was loose, P16E2 will be stored.
Confirm the fault first
Start by confirming the code. Turn the vehicle to the ON mode, clear the DTC with the HDS, wait for 10 seconds, and then check for Pending or Confirmed DTCs again. If P16E2 comes right back, the failure is duplicated and you can keep moving through the test path. If it does not return, treat it as intermittent for now. At that point, the system is OK at this time, so check for poor connections or loose terminals at the alternator and the PCM, and try to reproduce the captured conditions if that information is available.
Use companion code context to choose the path
Next, check the HDS again for Pending or Confirmed DTCs. If the companion LIN-related fault is also indicated, the path moves into a short-to-ground style check at the alternator connector. If that companion fault is not indicated, skip ahead to the open-circuit check between the alternator and the PCM.
Check whether the LIN circuit is shorted
For the short check, turn the vehicle to the OFF, LOCK mode and disconnect the alternator 1P connector. Check continuity between alternator 1P connector terminal No. 1 and body ground. If there is continuity, continue into the isolation check. If there is no continuity, move to the next failure-area check with the battery sensor disconnected and the alternator reconnected.
Isolate the shorted section or component
If the circuit shows continuity to ground at that point, jump the SCS line with the HDS and wait more than 1 minute. Keep watching continuity between the alternator 1P terminal and body ground while disconnecting the 12 volt battery sensor 2P connector, then PCM connector B, 51P, one at a time. If continuity goes away when one of those connectors is unplugged, the LIN wiring itself is considered OK, and the component whose disconnection made continuity disappear is the part called out by the path. If continuity does not go away, repair the short in the LIN battery sensor and LIN wire between the 12 volt battery sensor, the alternator, and PCM terminal B40.
Check the alternator-side failure path
If the first short check did not show continuity, turn the vehicle to the OFF, LOCK mode. Disconnect the 12 volt battery sensor 2P connector, reconnect the alternator 1P connector, and check continuity between 12 volt battery sensor 2P connector terminal No. 2 and body ground. If there is continuity here, the path calls for replacing the alternator. If there is no continuity, continue to the LIN open-circuit check.
Check the LIN wire for an open with the battery sensor disconnected
For the next open-circuit check, jump the SCS line with the HDS and wait more than 1 minute. With the vehicle in OFF, LOCK mode, the 12 volt battery sensor 2P connector disconnected, the alternator 1P connector disconnected, and PCM connector B, 51P, disconnected, check continuity between alternator 1P connector terminal No. 1 and PCM connector B terminal No. 40. If there is continuity, the LIN wire is OK. In that case, update the PCM if it does not have the latest software, or substitute a known-good PCM and recheck. If P16E2 goes away after the PCM update, troubleshooting is complete. If P16E2 goes away with the known-good PCM substituted, replace the original PCM. If there is no continuity, repair the open in the LIN wire between the alternator and PCM terminal B40.
Open-circuit path when the companion fault is not present
If the companion fault was not present earlier, the path goes directly to an open-circuit check. Turn the vehicle to the OFF, LOCK mode, jump the SCS line with the HDS, and wait more than 1 minute. Disconnect the alternator 1P connector and PCM connector B, 51P, then check continuity between alternator 1P connector terminal No. 1 and PCM connector B terminal No. 40. If there is continuity, the LIN wire is OK and the path calls for replacing the alternator. If there is no continuity, repair the open in the LIN wire between the alternator and PCM terminal B40.
Takeaway
The key with P16E2 is to prove whether the LIN circuit is shorted, open, or intact before condemning a module or alternator. Start with the loose terminal check, duplicate the code, follow the branch based on the companion fault status, and let the continuity checks separate wiring from component or PCM-side decisions. For more diagnostic training, visit stepdiagnostics.com.
Final check
Use the code confirmation and continuity checks to separate possible wiring faults from alternator or PCM-side decisions.
For more guided automotive diagnostics, visit STEP Diagnostics.
